Inspection system by charged particle beam and method of manufacturing devices using the system

ABSTRACT

An inspection apparatus and a semiconductor device manufacturing method using the same. The inspection apparatus is used for defect inspection, line width measurement, surface potential measurement or the like of a sample such as a wafer. In the inspection apparatus, a plurality of charged particles is delivered from a primary optical system to the sample, and secondary charged particles emitted from the sample are separated from the primary optical system and introduced through a secondary optical system to a detector. Irradiation of the charged particles is conducted while moving the sample. Irradiation spots of the charged particles are arranged by N rows along a moving direction of the sample and by M columns along a direction perpendicular thereto. Every row of the irradiation spots of the charged particles is shifted successively by a predetermined amount in a direction perpendicular to the moving direction of the sample.

TECHNICAL FIELD

[0001] The present invention relates to an inspection apparatus for theinspection of a defect, etc. of a pattern formed on a surface of anobject of inspection by using a plurality of electron beams. Moreparticularly, the present invention relates to an inspecting apparatusfor inspecting a pattern or the like with high throughput, which isformed on the surface of an object of inspection on the basis of animage data that in turn is formed by irradiating the object ofinspection with electrons and trapping secondary electrons varying inaccordance with characteristics and shapes of the surface thereof, as inthe case where a defect of a wafer is to be detected in thesemiconductor manufacturing process. In addition, the present inventionrelates to a method for manufacturing devices with a high yield by usingthe inspection apparatus according to the present invention.

[0002] The present invention is concerned with a charged particle beamapparatus for detecting secondary charged particles generating from thepoint of irradiation of a sample by irradiating the sample with thecharged particle beams and to a method for the preparation of a devicefor inspecting a defect of the device by means of the charged particlebeam apparatus.

[0003] The present invention relates to an apparatus for irradiating asample disposed on an XY stage with a charged particle beam and to adefect inspection apparatus or an exposure apparatus by utilizing theapparatus. Moreover, the present invention relates to a method for thepreparation of semiconductors by using this apparatus.

[0004] The present invention relates to a defect inspection apparatusand a defect inspection method for inspecting a defect of a sample suchas a semiconductor wafer or the like by comparing an image of the samplewith a reference image prepared in advance, and also relates to a methodfor the manufacturing semiconductor devices by using the defectinspection apparatus or method.

[0005] The present invention is concerned with an electron beamapparatus for performing various inspections on a sample by irradiatingthe sample with electron beams and measuring the secondary electron beamgenerated from the point of irradiation. More particularly, the presentinvention relates to an electron beam apparatus for performing variousoperations including the inspection of a defect of a pattern of anintegrated circuit having a minimum line width of 0.1 micron or lesswith high throughput, formed on a semiconductor wafer, measurement forCD (critical dimension), measurement for accuracy in alignment,measurement for voltage, etc.

[0006] The present invention relates to an electron beam apparatus forprojecting an image onto the plane of a detecting device, whichcomprises irradiating an aperture plate having a plurality of apertureswith an electron beam generated from an electron gun, deliveringsecondary electron beams generated from the sample into a secondaryoptical system after separation from a primary optical system, andenlarging the secondary electron with the secondary optical system.Further, the present invention relates to a method for the preparationof a device, which comprises evaluating a wafer during the process formanufacturing the wafer by using the electron beam apparatus accordingto the present invention.

[0007] The present invention is concerned with an electron beamapparatus that performs various operations including inspections of adefect of a pattern having a minimal line width of 0.1 micron or less,measurements for line widths, alignment accuracy measurements, voltagemeasurements, analysis of operations at high speed during the deviceoperations, and so on. Moreover, the present invention relates to amethod for the preparation of a device in which the yield is improved byevaluating a wafer during the manufacturing process by using theelectron beam apparatus according to the present invention.

[0008] The present invention relates to an electron beam apparatus and amethod for the preparation of a device by using the electron beamapparatus. More particularly, the present invention relates to anelectron beam apparatus that can perform various operations includinginspections of a defect of a sample with a device pattern having aminimal line width of 0.1 micron or smaller, line width measurements,alignment accuracy measurements, measurements of voltage on the surfaceof the sample, or measurements of high precision time resolution with ahigh throughput and reliability. Moreover, the present invention relatesto a method for the preparation of a device, which can improve yield byevaluating a wafer during the manufacturing process by using theelectron beam apparatus.

[0009] An object of the present invention is to provide an electron beamapparatus capable of performing a focusing an electronic optical systemthereof in an electronic optical manner as well as in a short time, anda semiconductor device manufacturing method using the same apparatus.

[0010] The present invention relates to an electron beam apparatus and amethod for the preparation of a device by using the electron beamapparatus. More particularly, the present invention relates to anelectron beam apparatus which can carry out inspections of a defect of asample having a device pattern with a minimal line width of 0.1 micronor smaller with high throughput and reliability and to the method forthe preparation of a device, which can improve a yield by evaluating awafer during the manufacturing process by using the electron beamapparatus according to the present invention.

[0011] The present invention is concerned with an electron beamapparatus for evaluating a pattern or the like formed on the surface ofa sample and to a method for the preparation of a device by evaluatingthe sample during or after the manufacturing process by using theelectron beam apparatus according to the present invention. Moreparticularly, the present invention is concerned with an electron beamapparatus that can perform various operations with high throughput andwith reliability, the various operations including inspections of adefect of a pattern of a device or the like having a minimal line widthof 0.1 micron or smaller on a sample, CD measurements, voltage contrastmeasurements, high time resolution voltage measurements, and so on.Moreover, the present invention is concerned with a method for thepreparation of a device by evaluating the sample during or after themanufacturing process by using the electron beam apparatus according tothe present invention.

[0012] The present invention relates to an E×B separator and aninspection apparatus for inspecting a semiconductor wafer by using theE×B separator. More particularly, the present invention relates to anE×B separator adapted to enlarge a region around the optical axis wherea uniform magnitude of the magnetic field or the electric field can beobtained and to an inspection apparatus that can perform variousoperations with high throughput and reliability by using the E×Bseparator, the various operations including inspections of a defect of asemiconductor wafer, measurements of pattern line widths, measurementsof accuracy of overlapping patterns or voltage measurements at a hightime resolution.

[0013] The present invention also relates to an apparatus forirradiating a charged beam against a sample loaded on an XY stage, andin more detail, to a charged beam apparatus provided with a differentialexhausting mechanism not in the XY stage but around a lens barrel and toa defect inspection apparatus or an exposing apparatus utilizing thesame charged beam apparatus, and further, to a semiconductormanufacturing method using those apparatuses described above.

[0014] The present invention also relates to an apparatus for evaluatinga wafer or the like having a pattern of minimum line width not greaterthan 0.1 μm with high throughput as well as with high reliability, andto a method for manufacturing a device by using the same apparatus withan improved yield.

[0015] In semiconductor processes, design rules are reaching 100 nm andproduction is on a transition from mass production with a few modelsrepresentative of DRAM into small-lot production with a variety ofmodels, such as a SOC (System on Chip). This will result in the increaseof the number of processes, and an improvement in yield for each processis essential; which makes it more important to inspect for defectsoccurring in each process. Accordingly, the present invention relates toan apparatus to be used in the inspection of a wafer after particularsteps in the semiconductor formation process, and to an inspectionmethod and apparatus using an electronic beam and further to a devicemanufacturing method using the same.

BACKGROUND ART

[0016] As prior art inspection apparatuses in connection with thepresent invention, an apparatus using a scanning electron microscope(SEM) has already been launched on the market. This apparatus isdesigned in such a way that an electron beam converged slenderly issubjected to raster scanning at a raster width having an extremely smallinterval, forming a SEM image by detecting the secondary electronemitted from the object of inspection upon scanning, and extracting adefect by comparing the SEM image at the same position of differentdice.

[0017] Further, many proposals have been made so far that a throughputcan be improved by using plural electron beams, that is, multi-beams.The proposals disclosed are directed primarily to the way of forming themulti-beams and to the way of detecting the multi-beams. No proposal,however, have been yet made as to an apparatus that has completed awhole system for a defect inspection apparatus.

[0018] In order to detect a defect of a mask pattern for use inmanufacturing semiconductor devices or a pattern formed on asemiconductor wafer, a scanning electron microscope has been used. Thescanning electron microscope requires a long time for inspection of awhole sample because the surface of the sample is scanned with oneelectron beam converged slenderly and the secondary electrons emittedfrom the sample are to be detected. In order to solve these problems, ithas been proposed that the electrons from a plurality of electronsources are focused on the plane of a sample through a deceleratingelectron field lens and scanned to deflect the secondary electronsemitted from the surface of the sample by means of a Wien's filter,thereby guiding the deflected secondary electrons to a plurality ofdetectors (Japanese Journal of Applied Physics, Vol. 28, No. 10,October, 1989, pp. 2058-2064).

[0019] For an apparatus for exposing a pattern of a semiconductorcircuit or the like to the surface of a sample such as a semiconductorwafer or the like or for inspecting a pattern formed on the surface ofsuch a sample by irradiating the surface of the sample with chargedparticle beams, such as electron beams or the like, or for an apparatusfor subjecting the sample to very high precision processing byirradiating it with the charged particle beams, a stage is used that canalign the sample in vacuum with high degree of precision.

[0020] When such a stage requires alignment at a very high level ofprecision, the stage uses a structure that it is supported in anon-contact way by means of a hydrostatic bearing. In thisconfiguration, the vacuum level in a vacuum chamber can be sustained byforming a differential exhaust mechanism for discharging high pressuregases within the range of the hydrostatic bearing so as to prevent thehigh pressure gases to be supplied from the hydrostatic bearing frombeing emitted directly into the vacuum chamber.

[0021] An example of such a conventional stage is shown in FIGS. 18A and18B. In the configuration as shown in FIGS. 18A and 18B, a top endportion of a lens barrel 2001 of a charged beam apparatus forirradiating a sample with charged beams, that is, a charged beamirradiation portion 2002, is mounted on a housing 2008 constituting avacuum chamber C. The inside of the lens barrel is made in a vacuumstate by discharging the air with a vacuum line 2010, and the vacuumchamber C is made in a vacuum state by discharging the air with a vacuumline 2011. Charged beams are irradiated from the top end portion 2002 ofthe lens barrel 2001 onto the sample S such as a wafer, etc. disposedthereunder.

[0022] The sample S is detachably held on a sample table 2004 byconventional means. The sample table 2004 is mounted on top surface of aY-directionally movable portion 2005 of an XY stage (hereinafterreferred to as “the stage”) 2003. The Y-directionally movable portion2005 is slidably mounted on an X-directionally movable portion 2006, andthe X-directionally movable portion 2006 is slidably mounted on a stagetable 2007.

[0023] The Y-directionally movable portion 2005 is installed with aplurality of hydrostatic bearings 2009 a on the surface (the left- andright-hand surfaces and the bottom surface in FIG. 18A) opposite to aguide surface 6 a of an X-directionally movable portion 2006, and theY-directionally movable portion is disposed so as to be movable in theY-direction (in the left- and right-hand directions in FIG. 18B) whilemaintaining a fine clearance from the guide surface by means of theaction of the hydrostatic bearing 2009 a. Similarly, the X-directionallymovable portion 2006 is installed with a plurality of hydrostaticbearings 2009 b and is movable in the X-direction (in the left- andright-hand directions in FIG. 18A) while maintaining a fine clearancebetween the hydrostatic bearings 2009 b and the guide surface 2007 a.

[0024] A differential exhaust mechanism system is further mounted aroundthe hydrostatic bearings so that no high pressure gases fed to thehydrostatic bearings leak into the inside of the vacuum chamber C. Thisconfiguration is shown in FIG. 19. Grooves 2017 and 2018 are disposeddoubly around the hydrostatic bearings 2009 and subjected to vacuumdischarging always by means of a vacuum line and a vacuum pump (notshown). This configuration allows the Y-directionally movable portion2005 held in vacuum in a non-contact state to be movable in theY-direction. The grooves 2017 and 2018 of a double structure are formedon the surface with the hydrostatic bearings 2009 of the movable part2005 disposed thereon so as to encircle the hydrostatic bearings. Theconfiguration of the hydrostatic bearings is a known one so that adetailed description will be omitted from the explanation that follows.

[0025] As is apparent from FIGS. 18A and 18B, the X-directionallymovable portion 2006 with the Y-directionally movable portion 2005loaded thereon is a concave with the top face upwardly open. TheX-directionally movable portion 2006 is provided with the hydrostaticbearings and the grooves in substantially the same configuration, and itis held in a non-contact state on a stage table 2007 so as to be movablein the X direction. By combining the movement of the Y-directionallymovable portion 2005 with the movement of the X-directionally movableportion 2006, the sample S is transferred horizontally to an optionalposition with respect to the top end portion of the lens barrel, thatis, the charged beam irradiation portion 2002, and it is irradiated atthe desired position with charged beams.

[0026] Hitherto, a defect inspection apparatus for inspecting a defectof a sample such as a semiconductor wafer or the like has been used in aprocess for manufacturing semiconductors, the defect inspectionapparatus being of a structure so as to inspect the defect of the sampleby detecting a secondary electron generated by the irradiation of thesample with a primary electron.

[0027] This defect inspection apparatus uses technology designed toautomate and render the inspection of defects of a sample more efficientby application of an image recognition technique. This technique isdesigned to subject pattern image data in a region of inspection on thesurface of the sample, obtained by the detection of the secondaryelectrons, and pre-stored reference image data on the surface of thesample, to a matching operation with a computer and to automaticallydetermine the presence or absence of defects on the sample on the basisof the result of the matching operation.

[0028] Nowadays, there is a great demand in the field of manufacturingsemiconductors to detect fine defects, as patterns are rendered finer.Under such circumstances, further improvements in precision ofrecognition are demanded for a defect inspection apparatus utilizing theimage recognition technique as described above.

[0029] Hitherto, the process for scanning electron beams in thedirection parallel to the direction of movement of a sample table andperpendicular thereto while continuously transferring the sample table(JP-A-10-134757, Japanese Patent Application Laid-Open) has been known.Another scanning process is known which involves irradiating the surfaceof a sample with a primary electron beam diagonally in two-dimensionswhile projecting in a one-axial direction at equal intervals. It hasfurther been known to perform inspections and so on by dividingelectrons from each electron gun into a plurality of electrons andscanning each beam in one direction while continuously moving the sampletable in the direction perpendicular to the scanning direction.

[0030] As an electron beam apparatus for use in inspecting a defect of amask pattern for use in manufacturing semiconductor devices or a patternformed on a semiconductor wafer, there is known an electron beamapparatus of the type that inspects defects of a pattern on the sample,which comprises irradiating an aperture plate having a plurality ofapertures with an electron beam emitted from a single electron gun toproduce a plurality of images of the apertures, delivering the resultingplural images of the apertures onto a sample, and projecting thesecondary electrons emitted from the sample onto the surface of adetector as an image by using a secondary optical system.

[0031] The conventional electron beam apparatus of that type, however,fails to take into account the dependency on the angle of the electronbeam emitted from the electron gun, and it treats the magnitude of theelectron beam as being uniform regardless of the angles of irradiationof the electron beam. In other words, the problem has not been takeninto consideration that, in the electron beams emitted from the electrongun, an electron beam having a high magnitude of illuminance is emittedin the direction of the optical axis, however, the illuminance(magnitude) of the electron beam is gradually decreased as the electronbeam becomes apart from the optical axis.

[0032] Further, there is the problem that the rate of detection of thesecondary electron emitted from the sample is high for the secondaryelectron emitted in the vicinity of the optical axis and that the rateof detection of the secondary electrons drops as the secondary electronsseparate from the optical axis. The conventional electron beamapparatus, however, fails to take this problem into consideration.

[0033] An electron beam apparatus using a plurality of electron beams isalso known, which is used for inspecting a defect in a circuit having afine circuit pattern, such as a super LSI circuit, or measuring a linewidth of such a circuit pattern. Such an electron beam apparatus usingmulti-beams was proposed in order to solve the problem of a conventionalelectron beam apparatus of the type using one electron beam for formingor inspecting such a fine circuit pattern because such a conventionalelectron beam apparatus requires a long period of time for processingand fails to gain a sufficient degree of throughput.

[0034] In connection with such an electron beam apparatus of the typeusing multi-beams, there is also known an electron beam apparatus, forexample, of the type having a large number of electron emitters arrangedin a matrix configuration, which is provided with an open mask betweenthe surface of a sample and the surface of inspection in order to solvethe problem that a level of precision in inspection could not beincreased because intervals of a detector for detecting reflectedelectrons or a secondary electrons is extremely narrow so that thereflected electrons or the secondary electrons are likely to invade thedetecting region from the adjacent irradiating region.

[0035] Moreover, there is known an electron beam apparatus of the typewhich forms a plurality of electron beams by irradiating a mask withplural apertures with an electron beam emitted from a single electrongun, in order to solve the problem that throughput is decreased due tothe fact that scanning requires a long period of time if a defect of apattern having a line width of approximately 0.1 micron is to beinspected by scanning the pattern on the sample with one electron beam.

[0036] In order to perform defect inspection, etc. on a sample having adevice pattern having a minimal line width of 0.1 micron or smaller, theability of a light system is in a limit of inspection from the viewpointof resolution on the diffraction of light and, therefore it has beenproposed that an inspection-evaluation apparatus that utilizes anelectron beam. The use of the electron beam, however, has the problemfrom the viewpoint of productivity because a drastic decrease inthroughput is caused, although resolution can be improved. An electronbeam apparatus that is modified so as to use multi-beams to improveproductivity is also known. More specifically, this known electron beamapparatus is configured in such a manner that the electron beams emittedfrom a single electron gun are irradiated onto a plurality of aperturesand the electron beams passed through the apertures are subjected toscanning of the surface of a sample (hereinafter referred to sometimesas “sample surface”), thereby allowing the secondary electron to beemitted from each image and guiding the secondary electron to each of aplurality of detectors for inspecting the sample.

[0037] When a pattern formed on a sample surface such as a semiconductorwafer is to be evaluated with high accuracy by using result of ascanning operation of the electron beam, it is necessary to considervariation in the height of the sample. This is because differences inthe height of the sample vary distances between a pattern on the surfaceof the sample and an objective lens by which the electron beam is to befocused on said pattern, and thereby focusing condition was notsatisfied, resulting in deterioration of resolution, which make itimpossible to perform an accurate evaluation.

[0038] In order to overcome this problem, an electron beam apparatus hasbeen suggested that performs a focusing operation of the electronicoptical apparatus in a manner whereby the light is irradiated againstthe sample surface at a certain angle, the reflected light thereof isutilized to measure the height of the sample, a measurement is fed backto the electronic optical system by which the electron beam is to befocused on the sample, and thereby the current and the voltage appliedto the components of the electronic optical system are controlled.

[0039] However, in a method for irradiating the light against the sampleat a certain angle, an optical component for reflecting the incidentlight, which is mainly composed of insulating material, should bedisposed in a space between the sample surface and a lower surface ofthe electronic optical system. Thereby, the space between the samplesurface and the lower surface of the electronic optical system has to bemade wider than is required, while on the other hand, the wider spacingmakes such problems as an aberration of the electronic optical systemnon-negligible. Accordingly, although it is required to perform focusingof the electronic optical system and simultaneously to solve suchproblems of aberration of the electronic optical system, such method bywhich both requirements are accomplish has not been suggested.

[0040] In addition, since the focusing of the electronic optical systemshould be performed taking into account not only the distance betweenthe sample surface and the lower surface of the electronic opticalsystem but also a charging condition on the sample surface and aspace-charge effect of the electron beam, if parameters relating to thefocusing of the electronic optical system are not measured in anelectronic optical manner, errors might possibly occur.

[0041] Further, there is another problem that, in a case that excitingcurrent of a magnetic lens included in the electronic optical system isregulated to perform the focusing operation, a period from when theexciting current being set to a predetermined value until when a focallength of the electronic optical system is stabilized, namely settlingtime, must be taken rather longer, and consequently it is difficult toperform the focusing quickly. In another case where exciting voltage ofan electrostatic lens is regulated to perform the focusing operation, ahigh voltage applied to the electrostatic lens shall be varied, whichresults in the same problem of longer settling time. Furthermore, thereis another problem that evaluation by the electron beam results in lowthroughput.

[0042] The present invention has been made with a view solving thevarious problems described above, and an object of the present inventionis to provide an electron beam apparatus capable of performing afocusing operation in an electronic optical system thereof in anelectronic optical manner as well as in a short time, and asemiconductor device manufacturing method using the same apparatus.

[0043] In a case that defects are to be inspected on a sample having aminimal line width of 0.1 micron or smaller, the inspection by means ofa optical light system has a limit due to the resolution due todiffraction of light. Therefore, an inspection-evaluation apparatususing an electron beam has been proposed. The use of the electron beamhas improved resolution, however, since it has an extremely decreasedthroughput, there is a problem from the point of view of productivity. Apatent application has been made for an invention relating to anelectron beam apparatus for inspecting a sample by using multi-beamswith the object to improve productivity, which comprises irradiating aplurality of apertures with electron beams emitted from a singleelectron gun and scanning the sample with the electron beams passedthrough the plural apertures, thereby guiding the secondary electronbeam generated from each image reciprocally to a detector withoutcausing crosstalk.

[0044] A variety of technologies have been reported on apparatuses forobserving and evaluating a sample including an insulating material.Among apparatuses installed with such technology, there are knownapparatuses installed with a scanning electron microscope, which has acharging detection function for evaluating charging state by measuringbeam current of a primary beam, a current absorbed into a sample, amountof electrons reflected from an irradiating apparatus, an amount ofsecondary electrons emitted, and the like.

[0045] Hitherto, there has been known an E×B energy filter for use inconducting an analysis of energy in a field where the electric field isorthogonal to the magnetic field, which allows charged particles to movestraight in the direction intersecting with both the electric field andthe magnetic field at right angles. This filter allows only the chargedparticles having a particular degree of energy in the electron beams totravel straight by means that deflection of the electron beams by theelectric field is canceled by the deflection of the electron beams bythe magnetic field.

[0046] As the energy filter of the E×B type, one having theconfiguration as shown in FIG. 4 is proposed. In FIG. 4, referencenumerals 1 and 1′ each denotes a magnetic pole piece held at earthvoltage; and reference numerals 2 and 2′ each denote an electrode. Avoltage +V is applied to the electrode 2 and a voltage −V is applied tothe electrode 2′. These voltages are equal to each other as an absolutevalue and variable. A charged electron can travel straight in thedirection intersecting both the electric field and the magnetic field,that is, in the direction perpendicular to the plane of the drawing.

[0047] A stage for accurately positioning a sample in a vacuumatmosphere has been used in an apparatus in which a charged beam such asan electron beam is irradiated onto a surface of a sample such as asemiconductor wafer so as to expose the surface of the sample to apattern of a semiconductor circuit or the like or so as to inspect apattern formed on the surface of the sample; it has also been used inanother apparatus in which the charged beam is irradiated onto thesample so as to apply an ultra-precise processing thereto.

[0048] When said stage is required to be positioned highly accurately,there has been employed a structure in which the stage is supported by ahydrostatic bearing in a non-contact manner. In this case, a vacuumlevel in a vacuum chamber is maintained by forming a differentialexhausting mechanism for exhausting a high pressure gas in an extent ofthe hydrostatic bearing so that the high pressure gas supplied from thehydrostatic bearing is not directly exhausted into the vacuum chamber.

[0049]FIGS. 18A and 18B show one of the examples of such stage accordingto the prior art. In the stage shown in FIGS. 18A and 18B, a tip portionof a lens barrel 2001 or a charged beam irradiating section 2002 of acharged beam apparatus for generating and irradiating a charged beamagainst a sample is attached to a housing 8 which makes up a vacuumchamber C. A sample S is detachably held on a sample table 2004. Otherstructures of the stage of FIGS. 18A and 18B will be described later.

[0050] A differential exhausting mechanism is provided surrounding thehydrostatic bearing 2009 b so that a high-pressure gas supplied to thehydrostatic bearing does not leak into the vacuum chamber C. This isshown in FIG. 19. Doubled grooves 2017 and 2018 are formed surroundingthe hydrostatic bearing 2009 b, and are regularly exhausted to vacuumthrough a vacuum pipe by a vacuum pump, though not shown. Owing to suchstructure, a Y directionally movable unit 2005 is allowed to move freelyin the Y direction in the vacuum atmosphere while supported innon-contact manner.

[0051] Those doubled grooves 2017 and 2018 are formed in a plane of themovable unit 2005 in which the hydrostatic bearing 2009 b is arranged,so as to circumscribe said hydrostatic bearing. Combining the Ydirectionally movable unit 5 with an X directionally movable unit 2006allows the sample S to be moved to any desired position in thehorizontal direction relative to the tip portion of the lens barrel orthe charged beam irradiating section 2002, so that the charged beam canbe irradiated onto a desired location of the sample.

[0052] However, the stage including a combination of the hydrostaticbearing and the differential exhausting mechanism as described above hasa problem that the overall structure thereof becomes more complex andrather larger in comparison with a stage of hydrostatic bearing typeused in the atmospheric air due to the differential exhausting mechanismincluded therein, resulting in lower reliability as a stage and also inhigher cost.

[0053] As for methods for compensating for magnification chromaticaberration and rotation chromatic aberration in the electronic opticalsystem, a method using a symmetric magnetic doublet lens is well known.Since no rotation chromatic aberration is generated in the electrostatic lens system, the magnification chromatic aberration iscompensated for by using a doublet lens.

[0054] As high integration of semiconductor devices andmicro-fabrication of patterns thereof advance, an inspection apparatuswith higher resolution and throughput has been desired. In order toinspect a wafer substrate of 100 nm design rules for defects, aresolution corresponding to 100 nm or finer is required, and theincreased number of processes resulting from high integration of thedevice causes an increase in an amount of inspection, which consequentlyrequires higher throughput. In addition, as multi-layer fabrication ofthe devices has progressed, the inspection apparatus has been furtherrequired to have a function for detecting a contact malfunction in a viafor interconnecting wiring between layers (i.e., an electrical defect).In the current trend, a defect inspection apparatus of optical methodhas been typically used, but it is expected that inspection apparatusesusing an electron beam may soon be mainstream, substituting for optionalinspection apparatuses from the viewpoint of resolution and ofinspection performance for contact malfunction. Defect inspectionapparatuses using electron beam methods, however, has a weak point thatit is inferior to that of optical method in throughput.

[0055] Accordingly, an apparatus having higher resolution and throughputand being capable of detecting the electrical defects is desired. It isknown that the resolution in the optical inspection apparatus is limitedto ½ of the wavelength of the light to be used, and it is about 0.2micrometer for an exemplary case of a visible light in practice.

[0056] On the other hand, in the method using an electron beam,typically a scanning electron beam method (SEM method) has been used,wherein the resolution thereof is 0.1 μm and the inspection time is 8hours per wafer (20 cm wafer). The electron beam method has thedistinctive feature that it can inspect for electrical defects (breakingof wire in the wirings, bad continuity, bad continuity of via); however,the inspection speed (sometime also referred to as the inspection rate)thereof is very low, and so the development of an inspection apparatuswith higher inspection speed is desirable.

[0057] Generally, since inspection apparatus is expensive and thethroughput thereof is rather lower as compared to other processingapparatuses, therefore the inspection apparatus has been used after animportant process, for example, after the process of etching, filmdeposition, CMP (Chemical-mechanical polishing) flattening or the like.

[0058] A inspection apparatus of scanning electron beam (SEM) will nowbe described. In the inspection apparatus of SEM, the electron beam iscontracted to be narrower (the diameter of this beam corresponds to theresolution thereof) and this narrowed beam is used to scan a sample soas to irradiate it linearly. On the one hand, moving a stage in thedirection normal to the scanning direction allows an observation regionto be irradiated by the electron beam as a plane area. The scanningwidth of the electron beam is typically some 100 μm. Secondary electronsemanating from the sample by the irradiation of said contracted andnarrowed electron beam (referred to as the primary electron beam) aredetected by a detector (a scintillator plus photo-multiplier (i.e.,photoelectron multiplier tube) or a detector of semiconductor type(i.e., a PIN diode type) or the like).

[0059] The coordinates for an irradiated location and an amount of thesecondary electrons (signal intensity) are combined and formed into animage, which is stored in a storage or displayed on a CRT (a cathode raytube). The above description demonstrates the principles of the SEM(scanning electron microscope), and defects in a semiconductor wafer(typically made of Si) being processed may be detected from the imageobtained in this method. The inspection rate (corresponding to thethroughput) depends on the amount of the primary electron beam (thecurrent value), the beam diameter thereof and the speed of response ofthe detector. The beam diameter of 0.1 μm (which may be considered to beequivalent to the resolution), a current value of 100 nA, and the speedof response of the detector of 100 MHz are currently the highest values,and in the case using those values the inspection rate has beenevaluated to be about 8 hours for one wafer having a diameter of 20 cm.This inspection rate, which is much lower compared with the case usinglight (not greater than {fraction (1/20)}), has been a serious drawback.

[0060] On one hand, as a method for improving the inspection rate, whichis a drawback of the SEM method, a multi beam SEM using a plurality ofelectron beams is well known. Although this method can improve theinspection rate by an amount of number of plurality of electron beams,there are other problems associated with this method that since theplurality of electron beams is irradiated from an oblique direction anda plurality of secondary electron beams from the sample is taken out inan oblique direction, only the secondary electrons emanated from thesample at the oblique direction could be captured by the detector, thata shadow is generated on an image, and that since it is difficult toseparate respective secondary electrons generated by respective pluralelectron beams, secondary electron signals are mixed with each other.

SUMMARY OF THE INVENTION

[0061] It can be noted herein that the conventional defect inspectionapparatuses with SEM applied thereto have a small beam dimension so thatthe dimension of the resulting image and raster width become small.Therefore, the conventional apparatuses have the problem that a longperiod of time is required for inspection of a defect of a sample.Moreover, they may present the problem that a quality SEM image cannotbe obtained because a wafer with an insulating material disposed on thesurface thereof is charged with electricity when the beam current ismade larger in order to accomplish high throughput.

[0062] Further, apparatuses using multi-beams present various problems:the overall configuration of the entire apparatus as well as theelectronic-optical system are not clear; the mutual interaction betweenthe electronic-optical system and the sub-systems is not at all clear sofar; moreover, as wafers as objects of inspection become larger,sub-systems of the apparatus must be compatible with larger-sizedwafers.

[0063] The present invention has been accomplished with the aboveproblems taken into account, and one object of the present invention isto provide an inspection apparatus in which an electronic-optical systemwith multi-beams can be used, and throughput can be improved, byharmonizing the electronic-optical system with the other partsconstituting the inspection apparatus.

[0064] Another object of the present invention is to provide aninspection apparatus that can inspect an object of inspection with highprecision by solving the problem relating to the SEM which arises fromthe charging with electricity.

[0065] A further object of the present invention is to provide a methodfor the preparation of a device at high yield by inspecting an object ofinspection such as a wafer and so on by means of the inspectionapparatus as described above.

[0066] The present invention provides an inspection apparatus forinspecting a pattern formed on an object of inspection by irradiatingthe pattern with an electron beam. The inspection apparatus comprises anelectronic-optical system having sources of electrons, an objectivelens, an E×B separator and an enlarging lens of at least one stage, theelectronic-optical system being adapted to shape a plurality of primaryelectron beams, irradiate the object of inspection with the plurality ofprimary electron beams, accelerate secondary electrons emitted by theirradiation with the primary electron beams by means of the objectivelens, separate the secondary electrons from the primary electron beamswith the E×B separator, and project an image of the secondary electronswith an enlarging lens of at least one stage after separation of thesecondary electrons from a primary optical system by the E×B separator.

[0067] The inspection apparatus further comprises a plurality ofdetectors for detecting the image of the secondary electrons projectedby the electronic-optical system, a stage device disposed for holdingthe object of inspection and transferring it relative to theelectronic-optical system, a working chamber arranged for accommodatingthe stage device and controlled so as to become in a vacuum atmosphere,a loader disposed for loading the object of inspection onto the stagedevice inside the working chamber, a voltage application mechanismsystem disposed in the working chamber for applying voltage to theobject of inspection, and an alignment control device for controllingthe alignment of the object of inspection relative to theelectronic-optical system by observing the surface of the object ofinspection for the alignment of the object of inspection relative to theelectronic-optical system. The vacuum chamber is supported by the aid ofa vibration isolator so as to block vibration from the floor on whichsaid inspection apparatus is disposed.

[0068] The loader of the above inspection apparatus includes a firstloading chamber and a second loading chamber, each being adapted to becapable of discretely controlling its atmosphere, a first transferringunit for transferring the object of inspection between the first loadingchamber and the outside thereof, and a second transferring unit disposedin the second loading chamber for transferring the object of inspectionbetween the inside of the first loading chamber and the stage device;wherein the inspection apparatus is further provided with amini-environment space partitioned to feed the object of inspection tothe loader.

[0069] Further, the inspection apparatus of this invention is providedwith a laser gauge interferometer for detecting coordinates of theobject of inspection on the stage device, wherein the coordinates of theobject of inspection are determined with the alignment control device byutilizing a pattern existing on the object of inspection. In this case,the alignment of the object of inspection may include the roughalignment to be effected within the mini-environment space and thealignments of the positions in the X- and Y-directions and in therotating direction to be effected on the stage device.

[0070] A further invention according to this application is directed toa method for manufacturing a device, which comprises detecting a defecton a wafer on the way or subsequent to the manufacturing process bymeans of the inspection apparatus.

[0071] The prior art apparatuses, however, cannot efficiently preventcrosstalk between plural electron beams and detect secondary electronsfrom the sample surface. On the other hand, the present invention has anobject to provide a charged particle beam apparatus that can prevent theoccurrence of crosstalk and guide emitted secondary electronsefficiently to the detector.

[0072] The charged particle beam apparatus 1000 according to the presentinvention may comprise at least one primary optical system forirradiating a sample with a plurality of primary charged particle beamsand at least one secondary optical system for leading the secondarycharged particles to at least one detector, wherein the plurality of theprimary charged particle beams are irradiated at positions apart fromone another by the distance resolution of the secondary optical system.

[0073] Further, the primary optical system is provided with a functionof scanning the primary charged particle beams at an interval wider thanthe interval of irradiation of the primary charged particle beams.

[0074] A stage device with a combination of the hydrostatic bearings andthe differential exhaust mechanism system shown in FIGS. 18A and 18B isarranged so as for the guide faces 2006 a and 2007 a opposite to thehydrostatic bearings 2009 to reciprocally move between the high pressuregas atmosphere of the hydrostatic bearing portion and the vacuumenvironment within the chamber, upon transferring the stage device. Atthis time, gases are adsorbed onto the guide faces while being exposedto the high-pressure gas atmosphere, and the gases adsorbed thereon areallowed to be dischargingon exposure to the vacuum environment. Theseactions are repeated. Therefore, whenever the stage device istransferred, a phenomenon occurs, in which the vacuum level within thechamber C is degraded, thereby rendering it difficult to conduct variousoperations, including exposure, inspection, processing, etc., by thecharged beams and contaminating the sample with foreign materials.

[0075] Another object to be achieved by the present invention is toprovide a charged beam apparatus that can perform various operations,including inspection, processing, and so on by means of charged beamswhile preventing a decrease in the vacuum level.

[0076] A further object to be accomplished by the present invention isto provide a charged beam apparatus disposed so as to produce a pressuredifferential between the region of irradiation of the charged beams anda support portion of the hydrostatic bearing, the charged beam apparatushaving a non-contact support mechanism by means of a hydrostatic bearingand a vacuum sealing mechanism system by means of the differentialexhaust.

[0077] A still further object of the present invention is to provide acharged beam apparatus adapted so as to reduce gases emitted from thesurface of a part opposite to the hydrostatic bearing.

[0078] A still further object of the present invention is to provide adefect inspection apparatus for inspecting the surface of a sample withthe charged beam apparatus as described above or an exposure apparatusfor delineating a pattern on the surface of the sample.

[0079] A still further object of the present invention is to provide amethod for manufacturing a semiconductor device by using the chargedbeam apparatus as described above.

[0080] The invention of this application is directed to an apparatus2000 adapted to irradiate the surface of a sample with a charged beam byloading the sample on the XY-stage and moving the sample to a chosenposition within a vacuum atmosphere. In this apparatus, the XY-stage isprovided with a non-contact support mechanism by means of thehydrostatic bearing and with a vacuum sealing mechanism by means ofdifferential exhaust; the XY-stage is further provided with a partitionfor rendering conductance smaller between a portion where the sample isirradiated with the charged beams and a support portion of the XY-stagefor supporting the hydrostatic bearings, and a pressure differentialoccurs between the region of irradiation with the charged beam and thesupport portion for the hydrostatic bearing.

[0081] In accordance with the present invention, the stage device canachieve alignment performance with high precision within a vacuumatmosphere by applying the non-contact support mechanism by means of thehydrostatic bearings to the support mechanism of the XY-stage with thesample loaded thereon and arranging the vacuum sealing mechanism bymeans of the operating exhaust around the hydrostatic bearings toprevent the high pressure gas fed to the hydrostatic bearings fromleaking into the vacuum chamber.

[0082] Moreover, the pressure at the position of irradiation with thecharged beams is unlikely to rise because the gases are arrangedunlikely to reach the position of irradiation of the charged beams bymeans of the partition apart from the position of irradiation with thecharged beams, by which conductance can be made smaller, even if thegases adsorbed on the surface of a sliding portion of the stage areemitted whenever the sliding portion of the stage is transferred fromthe high pressure gas portion into the vacuum environment. In otherwords, the above configuration can accomplish processing of the sampleby means of the charged beams with high precision without causing anycontamination on the surface of the sample because the degree of vacuumat the position of irradiation with the charged beams on the samplesurface can be stabilized and the stage can be driven with highprecision.

[0083] The present invention is directed to the charged beam apparatus2200 in which the differential exhaust structure is installed in thepartition. In accordance with this invention, the partition isinterposed between the hydrostatic bearing support portion and theregion irradiated y charged beam, and the inside of the partition isinstalled with a vacuum exhaust passage to provide the differentialexhaust mechanism. The differential exhaust structure can prevent gasesemitted from the hydrostatic bearing support portion from passingthrough the partition and entering the region of irradiation with thecharged beams. Therefore, the degree of vacuum at the position ofirradiation with the charged beams can be made further stable.

[0084] The invention is directed to the charged beam apparatus 2300 inwhich the partition is provided with a cold trap function. Generally, inthe pressure region having 10-7 Pa or higher, the major components ofthe residue gases in the vacuum atmosphere and the gases emitted fromthe surface of a material is water molecules. Therefore, if watermolecules can be emitted in an efficient manner, a high degree ofstability of vacuum can be sustained. On the basis of the concept asdescribed immediately above, this invention is configured such that acold trap, which is chilled at approximately −100° C. to −200° C., isdisposed at the partition in order to allow the cold trap to freeze thegases emitted at the side of the hydrostatic bearing and trap them. Theuse of the cold trap makes it impossible or difficult for the emittedgases to enter the side of the region of irradiation with charged beamso that it becomes possible to sustain the degree of vacuum in theregion of irradiation therewith in a stable manner. It is also to benoted herein as a matter of course that the cold trap is effective forthe elimination of gaseous organic molecules such as oils, which are amajor factor for impairing clean vacuum, as well as for the removal ofthe water molecule.

[0085] The invention of this application is directed to the charged beamapparatus 2400 which is provided with partitions at two locations in thevicinity of both positions of the region of irradiation with chargedbeam and the hydrostatic bearings. In accordance with this invention,partition that can reduce conductance is disposed at two locationsnearby the position of the region of irradiation with charged beam andthe hydrostatic bearings so that the vacuum chamber is eventuallydivided into three smaller chambers consisting of a charged beamirradiation chamber, a hydrostatic bearing chamber and an intermediatechamber, each having a smaller conductance. The pressure in each of thechambers is set such that the pressure in the charged particle beamirradiation chamber is the lowest and the pressure in the hydrostaticbearing chamber is the highest, while the pressure in the intermediatechamber is in between.

[0086] The three chambers constitute a vacuum exhaust system. Thearrangement of the partition enables the control the rate of variationin pressure at a low level even if a rise in pressure would occur in thehydrostatic bearing chamber by the emitted gases, because the pressurein the hydrostatic bearing chamber is set to be higher. Therefore, avariation in pressure in the intermediate chamber can be controlled to alower level by means of the partition, so that a variation of thepressure in the irradiation chamber can further be lowered to a lowerlevel by means of the additional partition. This arrangement of thepartition can reduce any variation in pressure to a level that does notsubstantially cause any problems.

[0087] The present invention is directed to a charged beam apparatus inwhich the gases to be fed to the hydrostatic bearings of the XY-stageare dry nitrogen gas or an inert gas of high purity. The invention isdirected to the charged beam apparatus in which the XY-stage issubjected to surface processing at least on the surface facing thehydrostatic bearing in order to reduce the emitted gases.

[0088] As described above, the gas molecules contained in the highpressure gases are adsorbed on the surface of the sliding portion of thestage when exposed to the high pressure gas atmosphere at thehydrostatic bearing portion, and they are caused to be released from thesurface of the sliding portion thereof and emitted as emitted gases,when the sliding portion thereof is exposed to the vacuum environment,thereby worsening the vacuum level. In order to control the lowering ofthe degree of vacuum, it is required to reduce an amount of the gasmolecules to be adsorbed on the sliding portion of the stage and todischarge the adsorbed gas molecules as quickly as possible.

[0089] In order to achieve this, it is effective to remove gaseouscomponents (such as organic materials, moisture, etc.), which are likelyto be adsorbed on the surface of the part yet unlikely to be eliminatedtherefrom, from the high pressure gas to be fed to the hydrostaticbearings by removing a sufficient amount of moisture from the highpressure gas to give dry nitrogen gas or an inert gas of high purity(e.g. highly pure nitrogen gas, etc.). The inert gas such as nitrogen islow in the rate of adsorption on the surface of the part compared withmoisture and organic materials and comparatively great in the speed atwhich it is eliminated from the surface thereof.

[0090] Therefore, when an inert gas of high purity from which moistureand organic materials are eliminated to the highest possible extent isused as the high pressure gas, the amount of gases to be emitted can becontrolled to a lower level and the emitted gases can be emittedquickly, upon transferal of the sliding portion from the hydrostaticbearing portion to the vacuum environment, thereby reducing the extentto which the degree of vacuum is degraded. Accordingly, it is possibleto reduce the rise in pressure when the stage is transferred.

[0091] Further, it is also effective to subject the structuring parts ofthe stage, particularly the part being transferred reciprocally betweenthe high pressure gas atmosphere and the vacuum environment, to surfaceprocessing thereby reducing an energy of adsorption with the gasmolecules. When a metal is used as a base material, the surfaceprocessing may be carried out, for example, by means of processing withTiC (titanium carbide) or TiN (titanium nitride), nickel plating,passivation treatment, electrolytic polishing, composite electrolyticpolishing, glass bead shot, and so on. When SiC ceramics is used as abase material, the surface processing may be carried out, for example,by means of coating with a fine SiC layer by means of CVD. Accordingly,it is further possible to reduce the rise in pressure when the stage istransferred.

[0092] The present invention is directed to a wafer defect inspectionapparatus for inspecting a defect on the surface of a semiconductorwafer by using the apparatus as described above. This invention providesan inspection apparatus that is high in inspection precision and causesno contamination of a sample, because the invention can realize aninspection apparatus that is highly accurate in the alignmentperformance of the stage and stable in the degree of vacuum within theregion onto which the charged beam is irradiated.

[0093] The present invention is directed to an exposure apparatus fordelineating a circuit pattern of a semiconductor device on the surfaceof a semiconductor wafer or a reticle by using the apparatus asdescribed above.

[0094] The present invention can provide an exposure apparatus that ishigh in exposure performance and causes no contamination of a sample,because this invention can realize an inspection apparatus that ishighly accurate in the alignment performance of the stage and stable inthe degree of vacuum within the region on which the charged beam isirradiated.

[0095] The present invention is also directed to a method formanufacturing a semiconductor by using the apparatus as described in theabove. This invention can provide a high quality fine semiconductorcircuit by manufacturing the semiconductor with the apparatus that hashigh accuracy stage alignment performance and a stable degree of vacuumin the region of irradiation with charged beam.

[0096] Conventional technology has the problem a deviation in theposition may be caused between an image of a secondary electron beamobtained by irradiation of an inspecting region on the surface of asample with a primary electron beam and a reference image prepared inadvance, so that precision of the inspection of the defect is lowered.This positional deviation may cause a big problem where part of aninspecting pattern is deleted from the inspecting image of the secondaryelectron beam due to a deviation of the irradiation region of theprimary electron beam with respect to the wafer. This problem cannot beovercome alone by technology that optimizes the matching region withinthe inspecting image. It is further to be noted that this problem canbecome a critical defect in the inspection of a highly fine pattern.

[0097] The present invention is completed on the basis of the abovefindings and it has an object to provide a defect inspection apparatusthat can prevent a decrease in precision of the inspection of a defectcaused by the deviation in the position between the inspecting image andthe reference image.

[0098] Moreover, the present invention has another object to provide amethod for manufacturing a semiconductor device, which can improve ayield of device products as well as prevent the loading of defectiveproducts by conducting inspections of a defect of samples by means ofthe defect inspection apparatus having the above configuration.

[0099] In order to achieve the above objects, the defect inspectionapparatus 3000 according to the present invention is concerned with adefect inspection apparatus for inspecting a defect of a sample, whichis composed of an image acquisition means for acquiring an image of eachof a plurality of inspecting regions which deviate from one anotherwhile overlapping partially with one another on the sample, a means forstoring a reference image, and a defect determination means fordetermining a defect of the sample by comparing the image of each of theplurality of the inspecting regions acquired by the image acquisitionmeans with the reference image pre-stored by the meaning means. As thesample as an object of inspection, there may be selected any sample onwhich a defect is to be inspected. For the present invention, asemiconductor wafer is particularly preferred because it can demonstrateexcellent effects.

[0100] The present invention comprises an image acquisition means thatis adapted to acquire the image of each of the plural inspecting regionswhich are deviated from one another while overlapping partially with oneanother on the sample, and the defect determination means fordetermining the defect of the sample by comparing the acquired image ofeach of the plural inspecting regions a stored reference image. Asdescribed above, the present invention can selectively utilize thereference image and the inspecting images less in the positionaldeviation in the subsequent step and consequently control a decrease inprecision of detecting a defect due to the positional deviation becausethe images of the inspecting regions at different locations can beacquired.

[0101] Moreover, even if the sample and the image acquisition means arelocated in a relationship in which part of an inspecting pattern mayusually be deleted from the inspecting image region, there is theextremely high probability that the entire inspecting pattern may belocated in any one region in which the images of the plural inspectingregions that are deviated in their positions from one another arecovered. Therefore, errors in detecting a defect which may be caused tooccur due to a partial deletion of the pattern can be prevented.

[0102] The comparing means may be arranged so as to determine if thesample is free from defects, for example, when the sample is subjectedto a so-called matching operation between each of the acquired images ofthe inspecting regions and the reference image and at least one image ofthe plural inspecting regions has no substantial difference from thereference image. Conversely, if the image of the entire inspectingregion is substantially different from the reference image, it isdetermined that the sample involved has a defect. This permits defectinspection with high precision.

[0103] In a preferred embodiment of the present invention, the defectinspection apparatus further comprises a charged particle irradiationmeans in which each of the plural inspecting regions is irradiated witha primary charged particle beam to generate a secondary charged particlebeam from the sample, wherein the image acquisition means is so arrangedas to acquire the image of each of the plural inspecting regions oneafter another by detecting the secondary charged particle beam emittedfrom each of the plural inspecting regions. As the charged particlebeam, an electron beam is preferred.

[0104] In a more preferred embodiment, the charged particle irradiationmeans comprises a source of the primary charged particles and adeflecting means for deflecting the primary charged particles and adeflecting means for deflecting the primary charged particles. Theplural inspecting regions are irradiated one after another with theprimary charged particles emitted by deflecting the primary chargedparticles emitted from the source of the particles with the deflectingmeans. In this embodiment, the position of the input image can bealtered with ease by the deflecting means, so that a plurality of theinspecting images at different positions can be acquired at high speed.In a further embodiment of the present invention, there are provided aprimary optical system for irradiating the sample with the primarycharged particle beam and a secondary optical system leading a secondarycharged particles to a detector.

[0105] The method for manufacturing the semiconductor according toanother embodiment of the present invention includes a step ofinspecting a defect of a wafer during the manufacturing process or as afinished product by using the defect inspection apparatus in each of theembodiments as described above. The other embodiments as well as theaction and features of the present invention will become furtherapparent in the following description.

[0106] In the conventional technology as described above, electrons asmany as three can be generated from one electron gun so that thedisposition of a number of lens barrels is required. Further, for theabove apparatuses, the electronic-optical system requires a partiallysemispherical inspection electrode. Moreover, the conventionaltechnology adopts a system of the type that inspects minute inspectingregions one after another, so that the inspecting regions on which theelectron beams are irradiated have to be changed frequently. Therefore,the inspecting surface (the sample) has to be transferred at anintermittent interval so that the time required for transferal of thesample is ineffective and consequently the time required for theinspection of the entire sample is considerably long.

[0107] Therefore, the present invention has the object to provide anelectron beam apparatus that can solve the problems prevailing in theconventional technology as described above and can conduct inspectionsefficient.

[0108] The electron beam apparatus 4000 according to the presentinvention is directed to an electron beam apparatus for detecting asecondary electron beam from a predetermined region on the surface ofthe sample while transferring the sample, which includes a primaryelectron beam irradiation device for irradiating the surface of thesample with a plurality of primary electron beams and a secondaryelectron detector for detecting a secondary electron beam from the pointof irradiation of each of the primary electron beams formed on thesurface of the sample. The primary electron beam irradiation apparatusis configured in such a manner that the points of irradiation of theplurality of the primary electron beams formed on the surface of thesample are disposed in rows N in the direction of movement of the sampleand in columns M in the direction perpendicular to the direction ofmovement of the sample and that each row of from row 1 to row N of thepoints of irradiation of the primary electron beams deviates one fromanother by a constant amount in both of the direction of movement of thesample and in the direction perpendicular thereto.

[0109] More specifically, the primary electron beam irradiationapparatus has an electron gun and an aperture plate having a pluralityof apertures forming a plurality of electron beams which form the pointsof irradiation of the primary electron beams in rows N and in columns Mupon receipt of the electrons emitted from the electron gun. Theapertures are disposed in such a manner that the electrons emitted fromthe electron gun are located within the range of a predeterminedelectron density. Further specifically, each of the points ofirradiation of the primary electron beams is arranged so as to scan thesample by (the distance between the adjacent rows)/(the number of thecolumns N) +α in the direction perpendicular to the direction ofmovement of the sample (in which α is the width of scanning in anoverlapped manner together with the point of irradiation of the primaryelectron beam in the adjacent row, it could be from −1% to +20% of thescanning width, and it is usually approximately 10% or smaller of thescanning width).

[0110] This arrangement can widen a width for irradiation with anelectron beam in the direction perpendicular to the direction ofmovement of the sample and conduct a continual inspection of the sampleby means of such a wide width therefor. Each of M and N is anindependent integral number which is greater than or equal to one.

[0111] The secondary electron beams to be detected by the secondaryelectron beam detector may be used for various measurements including,for example, measurements for a defect on the surface of a sample,measurements of a wire width of an integrated circuit to be formed onthe surface of a sample, voltage contrast measurements, alignmentprecision measurements, and so on.

[0112] Further, for the electron beam apparatus as described above, theprimary electron beam irradiation device is provided with a plurality ofthe electron guns, a plurality of aperture plates corresponding to theplural electron guns, and a plurality of primary electron beamirradiation systems in which the aperture plate corresponding to eachelectron gun can form the primary electron beam to be irradiated to thesurface of the sample. The primary electron beam of each of the primaryelectron beam irradiation systems is arranged so as to avoidinterference with the primary electron beams of the other primaryelectron beam irradiation systems. Further, it is possible to provide aplurality of the secondary electron beam detectors for each of theprimary electron beam irradiation systems. This apparatus allows aninspection of the sample with a wider scanning width while transferringthe sample, so that efficiency of inspection can be further increased.

[0113] The present invention has the object to provide an electron beamapparatus for detecting secondary electrons from a sample by means ofmulti-detectors by irradiating the sample with multi-beams, which cansolve the problem that the strength of the beam on the optical axis ofthe primary electron is different from that of the beam outside theoptical axis thereof and which can make the efficiency of detecting thesecondary electrons from the sample substantially uniform.

[0114] Further, the present invention has the object to provide anelectron beam apparatus for inspecting a secondary electron from asample with multi-detectors by irradiating the sample with multi-beams,wherein the electron beam apparatus can solve the problems that theefficiency of detection of the secondary electron emitted in thevicinity of the optical axis on the sample is higher than that ofdetection of the secondary electron emitted in the position apart fromthe optical axis thereof and that it can make efficiency of detection ofthe secondary electrons from the sample substantially uniform.

[0115] Further, the present invention has the object to provide a methodfor evaluating a device during the manufacturing process by using theapparatuses as described above.

[0116] In order to solve the problems as described above, the inventionis directed to an electron beam apparatus which irradiates an apertureplate having plural apertures with electron beams emitted from a sourceof the electron beams to create a plurality of images of the apertures;delivers the plural images of the apertures to a sample; separate thesecondary electrons emitted from the sample from a primary opticalsystem; to deliver the secondary electrons to a secondary opticalsystem; to enlarge the secondary electrons with the secondary opticalsystem; and projects the secondary electrons to the surface of adetector. In this electron beam apparatus, a single aperture plate isdisposed at a position deviated toward the side of the electron beamsource from the position of the image of the electron beam source formedby the lens of the primary optical system, so that the position of theaperture plate in the direction of the optical axis is disposed so as tominimize a difference of the beam strength from each aperture throughwhich the beam is delivered to the surface of the sample.

[0117] By minimizing the difference in beam strength between each of thebeams in the multi-beams to be delivered onto the surface of the samplein the manner as described above, the difference in beam strengthbetween the beam nearby the optical axis and the beam apart from theoptical axis can be made smaller so that the beams can be delivered ontothe surface of the sample in a uniform way. Therefore, the electron beamapparatus can improve precision in inspection and measurement.

[0118] Further, by reducing the difference in beam strength between thebeams in the multi-beams to be delivered onto the surface of the sample,the number of beams can be increased, and the multi-beams can beirradiated in a wider range. Therefore, the electron beam apparatus canfurther improve efficiency in inspection and measurement.

[0119] Moreover, the present invention is directed to the electron beamapparatus for projecting the secondary electron onto the surface of thedetector by irradiating the aperture plate having the plural apertureswith the electron beam emitted from the source of the electron beam tocreate the plural images of the apertures, delivering the plural imagesof the apertures to the sample, separating the secondary electronsemitted from the sample from the primary optical system, delivering thesecondary electrons to the secondary optical system, and enlarging thesecondary electrons with the secondary optical system.

[0120] In this electron beam apparatus, a single aperture plate isdisposed at the position deviated toward the side of the electron beamsource from the position of the image of the electron beam source formedby the lens of the primary optical system, and the amount of deviationof the position of the single aperture plate is set so as to minimizethe difference in the amount of inspection of the secondary electronbetween the plural apertures becomes rendered minimal when a samplehaving no pattern is disposed on the surface of the sample.

[0121] By minimizing the amount of detection of the secondary electronsbetween the apertures by the detector of the secondary optical system inthe manner as described above, this apparatus can control a variation inthe ratio of detection of the electron beams in the secondary opticalsystem, so that this invention can achieve high precision inspection andmeasurement, in addition to the features as described in the above.

[0122] Further, the present invention is directed to the electron beamapparatus, wherein a wafer during the manufacturing process is to beevaluated by means of the electron beam apparatus. The electron beamapparatus according to the present invention can evaluate the wafer at ahigh degree of precision and efficiency by evaluating the wafer duringthe manufacturing process.

[0123] In an apparatus of the type producing a plurality of electronbeams by irradiating an aperture plate having a plurality of apertureswith electron beams emitted from a single electron gun, reducing theelectron beam from each of the apertures with a primary optical system,and projecting and scanning the reduced electron beam onto the surfaceof the sample, there may be found the problem that each of the electronbeams cannot be projected on the desired position due to the distortionof the primary optical system. In addition, there is another problem inthis apparatus that visual field astigmatism is present in the primaryoptical system for projecting the reduced electron beam on the surfaceof the sample, so that the dimensions and the shapes of the electronbeams differ between the positions of the electron beams close to andoutside the optical axis of the primary optical system.

[0124] Furthermore, the apparatus has the problem that the secondaryelectron beam cannot be projected on the desired position of a group ofthe detectors due to the presence of aberration in the secondary opticalsystem for projecting the secondary electron beam emitted from thesample to the group of the detectors.

[0125] The present invention is proposed with the objects to solve theproblems inherent in the conventional electron beam apparatuses. One ofthe objects of the present invention is to provide an electron beamapparatus that can reduce astigmatism of the primary optical system bycorrecting the distortion of the primary optical system and theaberration of the secondary optical system. The other object of thepresent invention is to provide a method for the preparation of a devicethat can improve a yield of the devices by conducting a variety ofevaluations of the wafer during the manufacturing process by using theelectron beam apparatus according to the present invention.

[0126] In order to achieve the objects as described above, the presentinvention is directed to an apparatus for irradiating an aperture platehaving a plurality of apertures with an electron beam emitted from anelectron gun, projecting and scanning a reduced image of each of theprimary electron beams passed through the plurality of the apertures onthe sample by means of the primary optical system, and projecting thesecondary electron beam emitted from the sample onto the detector byenlarging the secondary electron beam with the secondary optical system,wherein the positions of the plurality of the apertures of the apertureplate are set so as to correct the distortion of the primary opticalsystem.

[0127] The present invention is directed to an electron beam apparatusfor the detection of the secondary electron beam emitted from a samplewith a detector composed of a plurality of detection elements byirradiating a first multi-aperture plate having a plurality of apertureswith the electron beams emitted from the electron gun, projecting andscanning the reduced image of the primary electron beam passed througheach of the plural apertures on the sample by means of the primaryoptical system, and enlarging the secondary electron beams with thesecondary optical system, the electron beam apparatus being disposedwith a second multi-aperture plate having a plurality of apertureslocated in the front of the detector, wherein the positions of theapertures formed in the second multi-aperture plate are set so as tocorrect the distortion of the secondary optical system.

[0128] The present invention as is directed to an electron beamapparatus for irradiating the aperture plate having a plurality ofapertures with the electron beam emitted from the electron gun,projecting and scanning the reduced image of the primary electron beampassed through the plurality of the apertures thereof on the sample, andprojecting an image of the secondary electron beam emitted from thesample onto the detector by means of the secondary optical system,wherein the shape of each of the apertures is set so as to correctvisual field astigmatism of the primary optical system.

[0129] The present invention provides an electron beam apparatus foracquiring an image data with a multi-channel by irradiating an apertureplate having a plurality of apertures with the electron beams emittedfrom the electron gun, projecting and scanning the reduced image of theprimary electron beam passed through each of the plural aperturesthereof on the sample by means of the primary optical system containingan E×B separator, and projecting the image of the secondary electronbeam emitted from the sample on the detector by means of an imagingoptical system, wherein the image of the secondary electron beam isformed on the deflecting main plane of the E×B separator at the sampleside and the image of the primary electron beam from each of theplurality of the apertures thereof is formed on the deflecting mainplane of the E×B separator.

[0130] The present invention is directed to an electron beam apparatus,which is selected from a group consisting of a defect inspectionapparatus, a line width measurement apparatus, an alignment precisionmeasurement apparatus, a voltage contrast measurement apparatus, adefect review apparatus and a stroboscopic SEM apparatus.

[0131] The electron beam apparatus of the present invention is directedto the electron beam apparatus that is so arranged as to irradiate thesample with the electron beams from the plurality of electron guns andto detect the secondary electron beams emitted from the sample by meansof a plurality of the detectors disposed so as to correspond to theplural electron guns. Further, the electron beam apparatus of thepresent invention can be used for conducting evaluations of the waferduring the manufacturing process.

[0132] In the known technology, it is not clear as to how the secondaryelectron can be detected specifically by a plurality of detectors andwhether a sample can be inspected and evaluated at high resolution.Further, the known technology has the problems that an electron beamcannot be converged slenderly because the electron beam is irradiateddiagonally onto the surface of a sample in the primary optical systemand an electrostatic objective lens and the sample are not arranged in arelationship of an axial symmetry.

[0133] Further, there is also known the technology of separating thesecondary electron beam from the sample by means of the E×B separatorand leading it to the detector. This known technology has the problemthat chromatic aberration is caused to occur because the amount and thedirection of deflection of the electron beam deflected by the electricfield of the E×B separator is different between the electron beam havinga low energy and the electron beam having a high energy. Moreover, italso has the problem that it is difficult to ensure a space for adeflector in the vicinity of the sample in the case where the E×Bseparator is disposed.

[0134] One of the objects to be achieved by the present invention is toprovide an electron beam apparatus of a specific configuration, in whichan electron beam apparatus of an optical system of an imaging projectiontype is provided with an E×B separator and can conduct variousoperations including inspections and evaluations of a sample with highthroughput and with high reliability by using a plurality of electronbeams.

[0135] Another object of the present invention is to provide an electronbeam apparatus that can converge an electron beam in a slender form.

[0136] A further object of the present invention is to provide anelectron beam apparatus that can correct a chromatic aberration to becaused by the use of the E×B separator.

[0137] A still further object of the present invention is to provide anelectron beam apparatus in which the optical systems are disposed in tworows and in plural columns and which can conduct inspections,evaluations, etc. of the sample with high throughput and with highreliability.

[0138] A still further object of the present invention is to provide anelectron beam apparatus in which the E×B separator and the deflector canbe disposed at optimal positions by allowing the E×B separator to bealso used as the deflector.

[0139] A still further object of the present invention is to provide amethod for the preparation of a device, which can evaluate a sampleduring the manufacturing process by using the electron beam apparatus asdescribed above.

[0140] The above objects can be achieved by the following aspects of thepresent invention. One of the inventions of this application is directedto an electron beam apparatus which comprises a primary optical systemhaving a single electron gun for discharging an electron beam, anaperture plate having a plurality of apertures, a plurality of lenses,and at least two E×B separators disposed in a spaced arrangement, theprimary optical system being disposed to irradiate the surface of thesample with the electron beam emitted from the electron gun, and asecondary optical system for separating a secondary electron beamemitted from the sample from the primary optical system by means one ofthe E×B separators, delivering it to a secondary electron beam detectiondevice, and detecting it with the secondary electron beam detectiondevice.

[0141] This electron beam apparatus is configured in such a manner thatthe electron beam from the electron gun is irradiated onto the apertureplate to form a plurality of images of the apertures of the apertureplate, the positions of the plurality of the images of the aperturesthereof are allowed to coincide with the respective positions of the E×Bseparators, and the directions of the electron beams to be deflected inthe electric field of the respective E×B separators are opposite to eachother, when looked on the plane of the sample. This configuration of theelectron beam apparatus allows the operations including inspections,evaluations, etc. of the sample with high throughput and with highreliability by using the plural electron beams. Moreover, this apparatuscan correct a chromatic aberration caused to be produced by the E×Bseparator. In addition, the electron beam can be converged in a slenderform. Therefore, the electron beam apparatus according to the presentinvention can ensure a high precision of inspection.

[0142] In another aspect of the invention relating to the electron beam,the amount of deflection of the electron beam to be deflected by meansof the electric field of each of the E×B separators may be opposite toeach other, when looked on the plane of the sample, although theirabsolute values are equal to each other.

[0143] For the electron beam apparatus having the above configuration,paths of the secondary electron beams deflected by the E×B separatorsmay be disposed in two rows and in plural columns so as to cause nointerference with one another. This arrangement can perform inspections,evaluations, etc. of the sample with high throughput and with highreliability.

[0144] In another aspect of the invention according to this application,there is provided an electron beam apparatus comprising a primaryoptical system having a single electron gun for generating an electronbeam, an aperture plate having a plurality of apertures, a plurality oflenses, and an E×B separator, the primary optical system being arrangedsuch that the electron beam generated from the single electron gun isirradiated onto the surface of a sample; and a secondary optical systemdisposed such that the secondary electron beam emitted from the sampleis separated from the primary optical system by means of the E×Bseparator and delivered to a secondary electron detection device forinspection, wherein the electron beam generated from the electron gun isirradiated on the aperture plate to form images of the plural aperturesof the aperture plate, the positions of the images of the aperturesthereof are allowed to agree with the position of the E×B separator, anda scanning voltage is superimposed on the electric field of the E×Bseparator so as to deflect the electron beam. This configuration permitsan optimal arrangement of the E×B separator and the deflector by usingthe E×B separator in common as the deflector.

[0145] In the one aspect and another aspect of the present invention,the electron beam apparatus may comprise a defect inspection apparatus,a line width measurement apparatus, a defect review apparatus, an EBtester apparatus and a voltage contrast measurement apparatus.

[0146] Another aspect of the invention of this application is tomanufacture a device by evaluating a wafer during the manufacturingprocess by using the electron beam apparatus as described above.

[0147] An object of the present invention is to provide an electron beamapparatus capable of performing a focusing operation of an electronicoptical system thereof in an electronic optical manner as well as inshort time, and a semiconductor device manufacturing method using thesame apparatus. In order to accomplish this object, the presentinvention has provided an electron beam apparatus in which a pluralityof primary electron beams is irradiated against a sample by a primaryoptical system; a plurality of secondary electron beams emanated fromthe sample is, after having passed through an objective lens, introducedinto a secondary optical system by an E×B separator; and, afterintroduction, spacing between respective secondary electron beams isexpanded by at least a single stage of lens and then respectivesecondary electron beams are detected by a plurality of detectors, saidapparatus characterized in that the objective lens is supplied with atleast three different exciting voltage, and at least three data aremeasured, which represent build up width of an electric signalcorresponding to an intensity of the secondary electron beam, whichelectric signal is obtained when a pattern edge parallel with a firstdirection is scanned in a second direction. This allows the focusingoperation of the electronic optical system to be performed in shorttime.

[0148] The electron beam apparatus described above may be arranged as alens barrel so as to face to a plurality of samples so that a primaryoptical system of each lens barrel may irradiate a plurality of primaryelectron beams onto the sample in a location different from those forother lens barrels. This allows to improve the throughput.

[0149] Preferably, the electron beam apparatus may be configured suchthat an exciting condition of the objective lens may be determined whilea pattern on the wafer is in its charged condition.

[0150] The present invention also provides an electron beam apparatuscharacterized in that a plurality of primary electron beams isirradiated against a sample by a primary optical system; a plurality ofsecondary electron beams emanated from the sample is, after havingpassed through an objective lens, introduced into a secondary opticalsystem by an E×B separator; and, after introduction, spacing betweenrespective secondary electron beams is expanded by at least a singlestage of lens and then respective secondary electron beams are detectedby a plurality of detectors.

[0151] In this electron beam apparatus, the objective lens comprises afirst electrode to which a first voltage near to that of an earth isapplied, and a second electrode to which a second voltage higher thanthe first voltage is applied, and is configured such that a focal lengthof the objective lens may be varied by controlling the first voltageapplied to the first electrode, and an exciting means for exciting theobjective lens comprises a means for changing a voltage to be applied tothe second electrode in order to greatly vary the focal length of theobjective lens, and another means for changing a voltage to be appliedto the first electrode in order to vary the focal length thereof inshort time. The present invention further provides a semiconductordevice manufacturing method for evaluating a wafer in the course of orafter finishing the process by using the electron beam apparatusdescribed above.

[0152] It is not necessarily apparent as to whether an electron beamapparatus can be commercially available, which can actually detectsecondary electron beams with a plurality of detectors and inspect andevaluate a sample at a high degree of resolution. Further, in this case,it is required to use two different modes in one electron beamapparatus, one mode being arranged so as to detect only a relativelylarge defect with high throughput yet with a relatively low degree ofresolution (hereinafter referred to sometimes as “standard mode”) andthe other mode being arranged so as to detect a very small defect at asmall throughput yet at a high degree of resolution (hereinafterreferred to sometimes as “high resolution mode”). It is to be notedherein, however, that a practically usable apparatus having such afunction has not been yet developed.

[0153] In addition, when the two modes are used in one apparatus, it isfurther required to alter a scanning width of multi-beams, a rate ofmagnification of an electrostatic lens of the secondary optical system,and so on. However, this may cause another problems that a gap ofscanning may be caused to be formed between the beams of the multi-beamswhen the scanning width is made narrower than the scanning width as setin the standard mode or the beam dimension of the beam in the secondaryoptical system does not agree with the dimension of a pixel of thedetector. The present invention has the object to solve these problems.

[0154] In order to solve the problems as described above, one of theinvention according to this application is directed to an apparatuscomprising a primary optical system and a secondary primary opticalsystem, the primary optical system being configured in such a mannerthat an electron beam emitted from a single electron gun is formed inmulti-beams by means of an aperture plate with a plurality of aperturesand a sample as an object of inspection is scanned with the multi-beamsby reducing it with an electrostatic lens having at least two stages,and the secondary optical system being configured in such a manner thatthe secondary electron beam emitted from the sample is separated fromthe primary optical system with an E×B separator after passing throughan electrostatic objective lens and delivered to a plurality ofdetectors by enlarging it with an electrostatic lens having at least onestage, wherein the sample is evaluated on the basis of dimensions of atleast two kinds of pixels so as to allow an evaluation of the sample bythe mode having a high throughput yet a relatively low resolution andthe mode having a small throughput yet a high resolution. Thisarrangement can accomplish inspections and evaluations, etc. of thesample with high throughput and with high reliability by using theplural electron beams. Further, this allows the use of the two modes,that is, the standard mode and the high-resolution mode, in oneapparatus.

[0155] In another aspect of the electron beam apparatus according to thepresent invention, a rate of reduction of the multi-beams in the primaryoptical system is associated with a rate of enlargement with theelectrostatic lens of the secondary optical system.

[0156] In a further aspect of the electron beam apparatus according tothe present invention, a crossover image in the primary optical systemis adapted to be formed on the main plane of the electrostatic objectivelens in the mode having a high throughput yet a relatively lowresolution.

[0157] In a still further aspect of the electron beam apparatusaccording to the present invention, the rate of enlargement of thesecondary optical system is adjusted with the electrostatic lensdisposed at the side of the detector from an aperture disposed in thesecondary optical system.

[0158] Another invention according to this application is directed tothe manufacturing of a device by evaluating the wafer during themanufacturing process by using the electron beam apparatus having theconfiguration as described above.

[0159] The conventional scanning microscopes suffer from the problemthat a great decrease in throughput is caused particularly when a samplehaving a wide area is to be evaluated because the surface of the samplehas to be scanned with fine electron beams. In addition, a chargingdetection function cannot always detect a charging state in a correctway because each kind of currents has to be measured at a high timeresolution.

[0160] The present invention has been completed on the basis of theproblems as described above and has the object to provide an electronbeam apparatus adapted to evaluate a sample at an improved throughputand with high reliability.

[0161] Another object of the present invention is to provide an electronbeam apparatus with an improved charging detection function and at animproved reliability of evaluation as well as with an improvedthroughput by irradiating the sample with a plurality of the electronbeams concurrently.

[0162] A further object of the present invention is to provide a methodfor manufacturing a device in which the sample during or after themanufacturing process is evaluated at a high manufacturing yield byusing the electron beam apparatus having the configuration as describedabove.

[0163] One of the inventions according to this application is concernedwith an electron beam apparatus having a primary optical system arrangedso as to generate a primary electron beam, converge it and scan a samplewith it, a secondary optical system having a lens of at least one stageadapted so as to deliver the secondary electron beam emitted from anelectron beam irradiation portion of the sample, and a detector fordetecting the secondary electron, wherein the secondary electron emittedfrom the electron beam irradiation portion of the sample is acceleratedand separated from the primary optical system with an E×B separator, itis delivered onto the secondary optical system, and it is then detectedby enlarging an image of the secondary electron with the lens;

[0164] wherein the primary optical system generates a plurality of theprimary electron beams and irradiates the sample concurrently with theplural primary electron beams, and a plurality of the detectors aredisposed so as to correspond to the number of the primary electronbeams;

[0165] wherein a retarding voltage application device is disposed forapplying a retarding voltage to the sample; and

[0166] wherein a charging investigation unit is disposed forinvestigating a charging state of the sample.

[0167] The electron beam apparatus according to the present invention isfurther provided with a function for determining an optimal retardingvoltage on the basis of information relating to the charging state fromthe charging investigation unit and applying the optimal retardingvoltage to the sample or a function for varying an amount of irradiationof the primary electron beam.

[0168] Another invention according to the present invention is concernedwith an electron beam apparatus which has an optical system forirradiating a sample with a plurality of electron beams and a chargingstate investigation unit that can evaluate a distortion of a pattern ora faded pattern on a particular portion of the sample, when an image isformed by detecting the secondary electron beams generated uponirradiation of the sample with the primary electron beams by means ofthe plural detectors and a charging state is evaluated as large when theextent of distortion of the distorted pattern or the fading extent ofthe faded pattern is determined to be large.

[0169] In the electron beam apparatus in each of the aspects of thepresent invention, in which the charging investigation function isarranged so as to apply a retarding voltage having a variable value tothe sample, there may be further provided with a device for displayingthe image in such a manner that the operator can evaluate the distortedpattern or the faded pattern by forming the image in the vicinity of aboundary at which a pattern density of the sample varies to a greatextent in such a state that at least two retarding voltages are applied.

[0170] A still further invention of this application provides the methodfor the preparation of a device, wherein a defect of a wafer during orafter the manufacturing process is detected by means of the electronbeam apparatus having the configuration as described above.

[0171] It is to be noted herein, however, that even if a conventionalexample of an E×B energy filter having the configuration as shown inFIG. 54 would be used as an E×B separator of an inspection apparatusadapted to evaluate a semiconductor wafer by obtaining an image data bymeans of electron reams, a region around the optical axis where theprimary electron beams travel straight without causing any substantialaberration cannot be rendered so wide.

[0172] One of the reasons is because a conventional E×B energy filterhas a complicated structure so that symmetry is not so good. In otherwords, no good symmetry makes it complicated in computing an aberrationbecause a three-dimensional analysis of the electric field or themagnetic field is required for computing the aberration. Therefore, along period of time is required for designing the optimal aberration.

[0173] Another reason resides in the fact that a region is narrow, wherethe electric field and the magnetic field are crossing the optical axisat right angles and the magnitudes of the electric field and themagnetic field are substantially uniform.

[0174] The present invention has been completed on the basis of theproblems prevailing in the conventional examples of the electron beamapparatuses and has one of the objects to provide an E×B separator thathas a simple configuration and permits a simple calculation ofaberration as well as a region around the optical axis where themagnitudes of the electric field and the magnetic field are uniform.

[0175] The second object of the present invention is to provide anelectron beam apparatus containing the E×B separator that can achievethe first object of the present invention and a method for thepreparation of a device by evaluating the semiconductor wafer by usingthe electron beam apparatus as described above.

[0176] In order to achieve the first object of the present invention,there is provided the E×B separator adapted to form an electric fieldand a magnetic field, each of which is crossing the optical axis atright angles and separates at least two electron beams which travel indifferent directions; which comprises:

[0177] an electrostatic deflector having a pair of electrodes forgenerating the electric field, each being in the form of a plate, whichare disposed so as for the distance between the electrodes to becomeshorter than the length of an electrode crossing the electric field; and

[0178] an electromagnetic deflector of a toroidal type or a saddle type,which can deflect the electron beams in the direction opposite to theelectrostatic deflector.

[0179] Further, the E×B separator may be configured in such a mannerthat the electrostatic deflector is provided with six electrodes forgenerating the rotatable electric fields.

[0180] Moreover, the E×B separator may preferably be configured in sucha manner that the electromagnetic deflector of the toroidal type or thesaddle type has two sets of electromagnetic coils capable of generatingthe electric field and the magnetic field in both directions and thatthe direction of deflection caused by the electromagnetic deflector canbe adjusted to become opposite to the direction of deflection caused bythe electrostatic deflector by adjusting a current ratio of the two setsof the electromagnetic coils.

[0181] In addition, the E×B separator is preferably configured in such amanner that the electrostatic deflector is disposed inside theelectromagnetic deflector of the toroidal type or the saddle type,thereby forming the electromagnetic deflector in two divisions. The twodivisions of the electromagnetic deflector may be readily combinedintegrally outside the outer periphery of the electrostatic deflector.Therefore, the E×B separator can be manufactured with ease.

[0182] Furthermore, the present invention provides an inspectionapparatus with the E×B separator installed therein for use in separationof the secondary electron beams from the primary electron beams, whichis configured so as to irradiate the semiconductor wafer with the pluralprimary electron beams and detect the secondary electron beams from thesemiconductor wafer with the plural detectors to give an image data andto evaluate the processed state of the semiconductor wafer on the basisof the image data.

[0183] An object of the present invention is to provide a charged beamapparatus having a simple structure capable of being made compactwithout employing a differential exhausting mechanism for an XY stage.Another object of the present invention is to provide a charged beamapparatus provided with a differential exhausting mechanism forexhausting a region on a surface of a sample to which a charged beam isto be irradiated, as well as for exhausting an inside of a housingcontaining an XY stage to vacuum. Still another object of the presentinvention is to provide a defect inspection apparatus for inspecting asurface of a sample for defects or an exposing apparatus for printing apattern on the surface of the sample by using either of the charged beamapparatuses described above. Yet another object of the present inventionis to provide a semiconductor manufacturing method for manufacturing asemiconductor device by using either of the charged beam apparatusesdescribed above.

[0184] In an apparatus of the present invention for irradiating acharged beam against a sample loaded on an XY stage, said XY stage isaccommodated in a housing and supported by a hydrostatic bearing in anon-contact manner with respect to said housing; said housing in whichsaid stage is accommodated is exhausted to vacuum; and a differentialexhausting mechanism is arranged surrounding a portion in said chargedbeam apparatus, where the charged beam is to be irradiated against asurface of said sample, so that a region on said sample to which saidcharged beam is to be irradiated may be exhausted to vacuum.

[0185] According to the charged beam apparatus of this invention, ahigh-pressure gas supplied for the hydrostatic bearing and leaked-outinto the vacuum chamber is primarily evacuated by a vacuum exhaustingpipe connected to the vacuum chamber.

[0186] Further, arranging the differential exhausting mechanism, whichfunctions to exhaust the region to which the charged beam is to beirradiated, so as to surround the portion to which the charged beam isto be irradiated, allows the pressure in the irradiation region of thecharged beam to be decreased to significantly lower level than that inthe vacuum chamber, thus achieving stably a vacuum level where theprocessing to the sample by the charged beam can be performed withoutany troubles. That is to say, the stage with a structure similar to thatof a stage of hydrostatic bearing type commonly used in the atmosphericpressure (a stage supported by the hydrostatic bearing having nodifferential exhausting mechanism) may be used to stably apply theprocessing by the charged beam to the sample on the stage.

[0187] In a charged beam apparatus of the present invention, a gas to besupplied to said hydrostatic bearing of the XY stage is dry nitrogen ora high-purity inert gas, and said dry nitrogen or high-purity inert gasis pressurized after having being exhausted from said housing containingsaid stage so as to be supplied again to said hydrostatic bearing.

[0188] According to the present invention, since the residual gascomponents in the vacuum housing are the high-purity inert gas, thereshould be no fear that the surface of the sample or any surfaces of thestructures within the vacuum chamber defined by the housing would becontaminated by water contents or oil and fat contents, and in addition,even if inert gas molecular is adsorbed onto the sample surface, oncebeing exposed to the differential exhausting mechanism or the highvacuum section of the irradiation region of the charged beam, said inertgas molecular would be released immediately from the sample surface, sothat the effect on the vacuum level in the irradiation region of thecharged beam can be minimized and the processing applied by the chargedbeam to the sample can be stabilized.

[0189] The present invention also provides a wafer defect inspectionapparatus for inspecting a surface of a semiconductor wafer for defectsby using either of the apparatuses described above. This allows toprovide an inspection apparatus which accomplishes positioningperformance of the stage with high precision and also provides a stablevacuum level in the irradiation region of the charged beam with lowcost. The present invention also provides an exposing apparatus forprinting a circuit pattern of a semiconductor device on a surface of asemiconductor wafer or a reticle by using either of the charged beamapparatuses described above. This allows to provide an exposingapparatus which accomplishes positioning performance of the stage withhigh precision and also provides a stable vacuum level in theirradiation region of the charged beam with low cost.

[0190] The present invention also provides a semiconductor manufacturingmethod for manufacturing a semiconductor by using either of theapparatuses described above, which allows a micro semiconductor circuitto be formed by of manufacturing a semiconductor with the apparatuswhich accomplishes positioning performance of the stage with highprecision and also provides a stable vacuum level in the irradiationregion of the charged beam.

[0191] In a symmetric doublet lens, for example, when a reduction lenssystem is to be fabricated, two stages of lens are required and a sizeratio of respective lenses should be equal to a reduction ratio thereof.For example, when the system with a reduction ratio of 1/10 is to befabricated, there has occurred such problems that, since a size of alens of a smaller size cannot be made smaller than that defined by apossible processing accuracy, for example, a bore diameter thereof isdetermined to be 5 mm Φ and a lens gap to be about 5 mm, andaccordingly, a lens of a larger side has to be of rather larger sizewith a bore diameter of 50 mmφ and a lens gap of 50 mm, and that, when amagnification ratio is to be varied in the practical apparatus, asymmetric condition would get out of order.

[0192] In the light of the problems described above, an object of thepresent invention is to provide an electronic optical system capable ofcontrolling the magnification by using a lens system with two or morestages and also capable of compensating for a magnification chromaticaberration by using a single lens. Another object of the presentinvention is to provide a method for evaluating a wafer in order to finda possible cause of deterioration of yield in the device manufacturingas soon as possible by using the apparatus described above.

[0193] The present invention provides an electron beam apparatus inwhich a plurality of electron beams is focused by a lens systemincluding a condenser lens and then is formed into an image on a sampleby an objective lens, said apparatus characterized in that a crossoverposition of said electron beam defined by a lens of a front stage ofsaid objective lens is set to be in a proximal position of said lenssystem side of said objective lens. In the concrete, said crossoverposition is located in said lens system side with respect to a principalplane of the objective lens. Setting the crossover position as describedabove allows to reduce the aberration, in particular the chromaticaberration otherwise appearing in the electron beam formed into an imageon the sample.

[0194] The above-described plurality of electron beams may be aplurality of electron beams which has been emitted from a singleelectron gun as a single beam and passed through a plurality ofapertures to be formed into said plurality of electron beams, aplurality of electron beams emitted from a plurality of electron guns,or a plurality of electron beams emitted from a plurality of emittersformed in a single electron gun. The present invention also provides adevice manufacturing method in which a wafer in the course ofmanufacturing process is evaluated by using the electron beam apparatusdescribed above.

[0195] The present invention employs a plurality of primary electronbeams, in which said plurality of electron beams is made to pass throughan E×B filter (Wien filter) to enter a surface of a sample at rightangles while making a scanning operation in one-dimensional direction(x-direction), and secondary electrons emanated from the sample areseparated from the primary electron beams by the E×B filter to beintroduced at an oblique direction with respect to an axis of theprimary electron beam and are formed into an image or focused on adetecting system by a lens system. A stage is moved along an orthogonaldirection (y-direction) with respect to a scanning direction(x-direction) of the primary electron beam and thereby a serial imagecan be obtained.

[0196] When the primary electron beam passes through the E×B filter, acertain condition where a force applied to the electron beam by theelectric field and that by the magnetic field are equal in intensity andopposite in direction (Wien condition) is established, so that theprimary electron beam can go straight ahead.

[0197] On the other hand, since the secondary electron beam has adirection opposite to that of the primary electron beam, the forceapplied to the secondary electron beam by the electric field and that bythe magnetic field have the same direction, so that the secondaryelectron beam is deflected from the axial direction of the primaryelectron beam. As a result, the primary electron beam and the secondaryelectron beam are separated from each other.

[0198] When the electron beam passes through the E×B filter, theaberration of the electron beam becomes greater in the case of beingdeflected in comparison with the case of straight advance, andtherefore, a plurality of detectors each corresponding to each of theprimary electron beams required to be of high accuracy is provided, andthe secondary electrons generated by one electron beam are introducedinto a corresponding detector by said image forming system withoutexception.

[0199] This make it possible to prevent a mixing of signals. Ascintillator plus photo-multiplier is used as a detector. A PIN diode(semiconductor detector) may also be used as a detector. The presentinvention employs sixteen primary electron beams each having a beamdiameter of 0.1 μm and a beam current of 20 nA, and a current valuethree times as much as that of the apparatus available on the marketcould be obtained.

[0200] Electron Gun (Electron Beam Source)

[0201] In the present invention, a thermal electron beam source isemployed as an electron beam source. An electron emitting (emitter)member is made of LaB₆. Other material may be used for the emittermember so far as it has a high melting point (low vapor pressure at hightemperature) and a small work function. Two kinds of methods areemployed to obtain a plurality of electron beams. One is a method wherea single electron beam is derived from a single emitter (with oneprojection) and then is passed through a thin plate with a plurality ofapertures formed therein (aperture plate) to obtain a plurality ofelectron beams, and the other is a method where a plurality ofprojections is formed in one emitter and a plurality of electron beamsis derived therefrom. Either case takes advantage of the property thatthe projection facilitates the emission of electron beam from the tipthereof. Other types of electron beam source, for example, a thermalelectric field emission type of electron beam source may be used to emitthe electron beam.

[0202] It is to be appreciated that the thermal electron beam sourcemethod is such that the electron emitting member is heated to emitelectrons, while the thermal electric field emission electron beamsource is such method in which a high electric field is applied to theelectron emitting member to emit electrons and further the electronemitting section is heated so as to stabilize the electron emission.

[0203] Vacuum Exhausting System

[0204] In the present invention, a vacuum exhausting system is composedof a vacuum pump, a vacuum valve, a vacuum gauge, a vacuum pipe and thelike, and exhausts to vacuum an electronic optical system, a detectorsection, a sample chamber, a load-lock chamber and the like according toa predetermined sequence. In each of those sections, the vacuum valve iscontrolled so as to accomplish a required vacuum level. The vacuum levelis regularly monitored, and in the case of irregularity, an interlockmechanism executes an emergency control of an isolation valve or thelike to secure the vacuum level. As for the vacuum pump, a turbomolecular pump may be used for main exhaust, and a dry pump of the Rootstype may be used as a roughing vacuum pump. The pressure at aninspection spot (an electron beam irradiating section) is practically inthe range of 10⁻³ to 10⁻⁵ Pa, more preferably, in a range of 10⁻⁴ to10⁻⁶ Pa as shifted by one digit down.

[0205] Control System

[0206] In the present invention, a control system is mainly composed ofa main controller, a controlling controller, and a stage controller. Themain controller is equipped with a man-machine interface, through whichan operator manipulates the controller (a variety ofinstructions/commands, entry of a recipe, instructions to start aninspection, switching between an automatic inspection mode and a manualinspection mode, an input of all of the commands required in the manualinspection mode and so forth). In addition, the main controller furtherexecutes communication with a host computer in a factory, a control of avacuum exhausting system, control of carrying and positioning operationsof a sample such as a wafer, an operation for sending commands andreceiving information to/from the other controlling controllers and/orstage controller and so fourth.

[0207] Further, the main controller has a function to obtain an imagesignal from an optical microscope, and also has a stage vibrationcompensating function for compensating a deterioration in the image byfeeding back a fluctuation signal of the stage to an electronic opticalsystem, and an automatic focal point compensating function for detectinga displacement of the sample observation point in the Z direction (inthe axial direction of the secondary optical system) and feeding backthe detected displacement to the electronic optical system so as toautomatically compensate the focal point. Sending and receivingoperations of the feedback signal to/from the electronic optical systemand sending and receiving operations of the signal to/from the stage areperformed via the controlling controller and the stage controllerrespectively.

[0208] The controlling controller is mainly responsible for the controlof the electronic optical system (an electron gun, a lens, an aligner, acontrol of a high-precision power supply for a Wien filter or the like).In specific, the controlling controller performs a control operation,for example, an automatic voltage setting for each of the lens systemsand the aligners in response to each operation mode (gang control), sothat a constant electron current may be regularly irradiated against theirradiation region even if the magnification is changed, and voltages tobe applied to each of the lens systems and the aligners may beautomatically set in response to each magnification and so forth.

[0209] The stage controller is mainly responsible for control regardingthe movement of the stage so that precise movement in the X and the Ydirections may be on the order of μm (with tolerance of about ±0.5 μm).Further, in the present stage, control at the rotational direction (θcontrol) is also performed with a tolerance equal to or less than about±0.3 seconds.

[0210] Inspection Procedure

[0211] In the present invention, an inspection procedure is conducted asdescribed below (see FIG. 63). Generally, since an inspection apparatususing an electron beam is expensive and the throughput thereof is ratherlower than that provided by other processing apparatuses, this type ofinspection apparatus is currently applied to a wafer after an importantprocess (for example, etching, film deposition, or CMP (chemical andmechanical polishing) flattening process) which is considered that theinspection is required most.

[0212] A wafer to be inspected is, after having been positioned on anultra-precise X-Y stage through an atmosphere transfer system and avacuum transfer system, secured by an electrostatic chucking mechanismor the like, and then a defect inspection is conducted according to aflow chart shown in FIG. 63. At first, if required, a position of eachof dies is checked and/or a height of each location is sensed, and thosevalues are stored. In addtion, an optical microscope is used to obtainan optical microscope image in an area of interest possibly includingdefects or the like, which may also be used in, for example, thecomparison with an electron beam image.

[0213] Then, recipe information corresponding to the kind of the wafer(for example, after which process the inspection should be applied; whatthe wafer size is, 20 cm or 30 cm, and so on) is entered into theapparatus, and subsequently, after a designation of an inspection place,a setting of an electronic optical system and a setting of an inspectioncondition being established, a defect inspection is conducted typicallyat real time while simultaneously obtaining the image. A fast dataprocessing system with an algorithm installed therein executes aninspection, such as the comparisons between cells, between dies or thelike, and any results would be output to a CRT or the like and stored ina memory, if desired. Those defects include a particle defect, anirregular shape (a pattern defect) and an electric defect (a broken wireor via, a bad continuity or the like), and the fast data processingsystem also can automatically and at real-time distinguish andcategorize them according to a defect size, or whether their being akiller defect (a critical defect or the like which disables a chip).

[0214] The detection of the electric defect may be accomplished bydetecting an irregular contrast. For example, since a location havingbad continuity would generally be charged positive by electron beamirradiation (about 500 eV) and thereby its contrast would be decreased,the location of bad continuity can be distinguished from normallocations. The electron beam irradiation means in that case designatesan electron beam generation means (means for generating thermalelectron, UV/photoelectron) with lower energy arranged in order toemphasize the contrast by a potential difference, in addition to theelectron beam irradiation means used for a regular inspection. Beforethe electron beam for inspection is irradiated against the objectiveregion for inspection, the electron beam having that lower energy isgenerated and irradiated.

[0215] In the case of a map-projecting method in which the object can bepositively charged by the irradiation of the electron beam forinspection, the electron beam generation means with lower potential isnot necessarily arranged separately, depending on the specification ofthe system for the method. Further, the defect may be detected based onthe difference in contrast (which is caused by the difference in flowability of elements depending on the forward or backward direction)created by, for example, applying a positive or negative potentialrelative to reference potential to a wafer or the like. This electronbeam generation means may be applicable to a line-width measuringapparatus and also to an aligning accuracy measurement.

[0216] Cleaning of Electrode

[0217] Since, while an electron beam apparatus according to the presentinvention is operated, a target substance is extricated by a proximityinteraction (charging of particles in the proximity of a surface) andattracted to a high-voltage region, an organic substance would bedeposited on a variety of electrodes used for forming or deflecting anelectron beam. Since the insulating material gradually depositing on thesurface of the electrodes by the electric charge affects adversely onthe forming or deflecting mechanism for the electron beam, accordinglythose deposited insulating material must be removed periodically. Toremove the insulating material periodically, an electrode adjacent tothe region where the insulating material has been deposited is used togenerate the plasma of hydrogen, oxygen, fluorine or compounds includingthem, such as HF, O₂, H₂O, C_(M)F_(N) or the like, in the vacuum and tocontrol the plasma potential in the space to be a potential level(several kV, for example, 20V-5 kV) where the spatter would be generatedon the electrode surface, thereby allowing only the organic substance tobe oxidized, hydrogenated or fluorinated and removed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0218]FIG. 1 is a partially cross sectional elevation view illustratingmain components of an inspection apparatus of a first embodimentaccording to the present invention taken along the line A-A of FIG. 2.

[0219]FIG. 2 is a plan view illustrating those main components of theinspection apparatus illustrated in FIG. 1 taken along the line B-B ofFIG. 1.

[0220]FIG. 3A is a cross sectional view of a mini-environmental unit ofFIG. 1 taken along the line C-C of FIG. 1,and FIG. 3B is a sectionalview of another mini-environmental unit.

[0221]FIG. 4 is a cross sectional view of a loader housing taken alongthe line D-D of FIG. 1.

[0222]FIGS. 5A and 5B are enlarged views of a wafer rack, wherein FIG.5A is a side elevational view and FIG. 5B is a cross sectional viewtaken along the line E-E of FIG. 5A.

[0223]FIGS. 6A and 6B illustrate respectively first and secondalternatives of the supporting method of the main housing.

[0224]FIG. 7 is a schematic view illustrating a general configuration ofan electronic optical apparatus of a second embodiment according to thepresent invention to be used in the inspection apparatus of FIG. 1.

[0225]FIG. 8 illustrates a physical relationship defining a location ofeach aperture of a multi-aperture plate used in a primary optical systemof the electronic optical apparatus of FIG. 7.

[0226]FIG. 9 illustrates a potential applying mechanism.

[0227]FIGS. 10A and 10B illustrate an electron beam calibrationmechanism, wherein FIG. 10A is a side elevational view and FIG. 10B is aplan view.

[0228]FIG. 11 is a schematic diagram illustrating an alignmentcontroller for a wafer.

[0229]FIG. 12 is a flow chart for a semiconductor device manufacturingmethod of one embodiment according to the present invention.

[0230]FIG. 13 is a flow chart for a lithography process, a core processin a wafer processing process of FIG. 12.

[0231]FIG. 14A is a schematic diagram of an optical system in anelectron beam apparatus of a third embodiment according to the presentinvention.

[0232]FIG. 14B is an enlarged view of an image on a sample by amulti-beam.

[0233]FIG. 15 illustrates a secondary optical system and an angularaperture in the third embodiment of the present invention.

[0234]FIG. 16 illustrates a relationship between an aberration and anangular aperture “αi” on a surface 10 of a sample.

[0235]FIG. 17A is a plan view of a multi-emitter, and

[0236]FIG. 17B is a cross sectional view taken along the line 17B-17B ofFIG. 17A.

[0237]FIGS. 18A and 18B are cross sectional views of a vacuum chamberand an XY stage of a charged beam apparatus according to the prior art,wherein FIG. 18A is a front elevational view and FIG. 18B is a sideelevational view.

[0238]FIG. 19 is a perspective view of an exhaust gas dischargingmechanism used in for the XY stage of FIGS. 18A and 18B.

[0239]FIGS. 20A and 20B are cross sectional views of a vacuum chamberand an XY stage of a charged beam apparatus of a fourth embodimentaccording to the present invention, wherein FIG. 20A is a frontelevational view and FIG. 20B is a side elevational view.

[0240]FIG. 21 is a cross sectional view of a vacuum chamber and an XYstage of a charged beam apparatus of a fifth embodiment according to thepresent invention.

[0241]FIG. 22 is a cross sectional view of a vacuum chamber and an XYstage of a charged beam apparatus of a sixth embodiment according to thepresent invention.

[0242]FIG. 23 is a cross sectional view of a vacuum chamber and an XYstage of a charged beam apparatus of a seventh embodiment according tothe present invention.

[0243]FIG. 24 is a cross sectional view of a vacuum chamber and an XYstage of a charged beam apparatus of an eighth embodiment according tothe present invention.

[0244]FIG. 25 is a schematic diagram illustrating an optical system anda detection system of a ninth embodiment according to the presentinvention, which are to be arranged in a lens barrel shown in either ofFIGS. 18 to 24.

[0245]FIG. 26 is a schematic diagram illustrating an exemplaryconfiguration of a defect inspection apparatus according to a tenthembodiment of the present invention.

[0246]FIG. 27 illustrates some examples of a plurality of images to beinspected which is obtained by the defect inspection apparatus of FIG.26, and an example of a reference image.

[0247]FIG. 28 is a flow chart illustrating a flow of a main routine forwafer inspection in the defect inspection apparatus of FIG. 26.

[0248]FIG. 29 is a flow chart illustrating a detailed flow of asub-routine in a process for obtaining image data for a plurality ofregions to be inspected (step 3304) in the flow chart of FIG. 28.

[0249]FIG. 30 is a flow chart illustrating a detailed flow of asub-routine in a comparing process (step 3308) of FIG. 28.

[0250]FIG. 31 is a schematic diagram illustrating an exemplaryconfiguration of a detector in the defect inspection apparatus of FIG.26.

[0251]FIG. 32 is a schematic diagram illustrating a plurality of regionsto be inspected which are displaced one from another while beingpartially superimposed one on another on a semiconductor wafer surface.

[0252]FIG. 33 is a schematic diagram illustrating a configuration of ascanning electron beam apparatus included in a defect inspectionapparatus of an 11th embodiment according to the present invention.

[0253]FIG. 34 is a schematic diagram illustrating a configuration ofmain elements of an electron beam apparatus of a 12th embodimentaccording to the present invention.

[0254]FIG. 35A is a plan view of an aperture plate in the apparatus ofFIG. 34, FIGS. 35B and 35C are plan views showing arrangement of theapertures.

[0255]FIG. 36 illustrates an arrangement of primary electron beamirradiation points formed on a surface of a sample by the electron beamapparatus of FIG. 34.

[0256]FIG. 37 is a schematic diagram illustrating a configuration of anelectron beam apparatus of a 13th embodiment according to the presentinvention.

[0257]FIG. 38 is a schematic diagram illustrating an arrangement of anoptical system of an electron beam apparatus of a 14th embodimentaccording to the present invention.

[0258]FIG. 39 illustrates an example of the multi-aperture plate to beused in the electron beam apparatus of FIG. 38.

[0259]FIG. 40 illustrates an example of a detector aperture plate to beused in the electron beam apparatus of FIG. 38.

[0260]FIGS. 41A and 41B illustrate respectively a multi-aperture plateof another example to be used in the electron beam apparatus of FIG. 38.

[0261]FIG. 42 is a schematic diagram illustrating an optical system inan electron beam apparatus of a 15th embodiment according to the presentinvention.

[0262]FIG. 43 illustrates a condition where a plurality of opticalsystems in the electron beam apparatus of FIG. 42 is arranged so as foreach of them to be disposed in parallel on a wafer in the array of 2rows×multiple columns.

[0263]FIG. 44A is a view showing a brief configuration of an electronbeam apparatus according to a 16th embodiment of the present invention,

[0264]FIG. 44B is a plan view showing apertures of a multi-apertureplate,

[0265]FIG. 44C a diagram showing structure for applying voltage to anobjective lens.

[0266]FIG. 45 is composed of FIGS. 45A and 45B, wherein

[0267]FIG. 45A is a graph illustrating a relation between a voltageapplied to an objective lens and a build-up width of an electric signal,and

[0268]FIG. 45B is a graph for explaining the build-up width of theelectric signal.

[0269]FIG. 46 is a diagram illustrating a schematic configuration of anoptical system of an electron beam apparatus according to a 17thembodiment of the present invention.

[0270]FIG. 47 is a plan view illustrating respective arrangements ofapertures formed in a first aperture plate and a second aperture plateof the electron beam apparatus of FIG. 46.

[0271]FIG. 48 is a diagram illustrating a schematic configuration of anelectron beam apparatus according to an 18th embodiment of the presentinvention.

[0272]FIG. 49 a plan view illustrating a positioning relation amongapertures formed in a multi-aperture plate used in a primary opticalsystem of the electron beam apparatus of FIG. 48.

[0273]FIG. 50A is a diagram for explaining an evaluation location and anevaluation method of charging, and FIG. 50B is a diagram for comparingcontrasts of signal intensity.

[0274]FIG. 51 is a cross sectional view of an E×B separator according toa 19th embodiment of the present invention, taken on a plane orthogonalto an optical axis thereof.

[0275]FIG. 52 is a cross sectional view of an E×B separator according toa 20th embodiment of the present invention, taken on a plane orthogonalto an optical axis thereof.

[0276]FIG. 53A is a diagram illustrating a schematic configuration of adefect inspection apparatus for wafer according to a 21st embodiment ofthe present invention, capable of employing the E×B separator of FIG. 51or 52, and

[0277]FIG. 53B is a diagram illustrating a positioning relation amongapertures formed in a multi-aperture plate.

[0278]FIG. 54 is a diagram illustrating a schematic configuration of anE×B energy filter according to a prior art.

[0279]FIG. 55 is a cross sectional view illustrating a vacuum chamberand an XY stage of a charged beam apparatus according to a 22ndembodiment of the present invention.

[0280]FIG. 56 shows an example of a differential exhausting mechanismprovided in the charged beam apparatus of FIG. 55.

[0281]FIG. 57 is a block diagram illustrating a circulation pipingsystem for gas of the charged beam apparatus of FIG. 55.

[0282]FIG. 58 is a diagram illustrating a schematic configuration of anoptical system and a detecting system of a charged beam apparatusaccording to a 23rd embodiment of the present invention.

[0283]FIG. 59 is a diagram illustrating a schematic configuration of anelectron beam apparatus according to the present invention.

[0284]FIG. 60 is a plan view of an aperture plate used in the electronbeam apparatus of FIG. 58.

[0285]FIG. 61 is a diagram illustrating a simulation of an objectivelens of a charged beam apparatus according to a present invention.

[0286]FIG. 62 is a graph illustrating a result of the simulation of FIG.61.

[0287]FIG. 63 is an inspection flow diagram illustrating a procedure ofinspection.

[0288]FIG. 64 is a horizontal cross sectional view illustrating anelectron beam deflecting system.

[0289]FIG. 65 is a side elevational view illustrating a deflectingcondition of beam in the beam deflecting system.

[0290]FIG. 66 is a plan view for explaining a method for irradiating aprimary electron beam according to the present invention. and

[0291]FIG. 67 is an inspection flow diagram illustrating a procedure ofinspection.

EMBODIMENTS OF THE INVENTION

[0292] With reference to FIGS. 1 and 2, a first embodiment of thepresent invention will be explained in the form of a semiconductortesting apparatus for testing, as an object under testing, a substrate,i.e., a wafer which has patterns formed on the surface thereof. FIGS. 1and 2 illustrate main components of a semiconductor testing apparatus 1according to this embodiment in elevation and a plan view, respectively.

[0293] The semiconductor testing apparatus 1 of this embodimentcomprises a cassette holder 10 for holding cassettes which stores aplurality of wafers; a mini-environment device 20; a main housing 30which defines a working chamber; a loader housing 40 disposed betweenthe mini-environment device 20 and the main housing 30 to define twoloading chambers; a loader 60 for loading a wafer from the cassetteholder 10 onto a stage device 50 disposed in the main housing 30; and anelectro-optical device 70 installed in the vacuum main housing 30. Thesecomponents are arranged in a positional relationship as illustrated inFIGS. 1 and 2. The semiconductor testing apparatus 1 further comprises apre-charge unit 81 disposed in the vacuum main housing 30; a potentialapplying mechanism 83 (see in FIG. 8) for applying a to a wafer; anelectron beam calibration mechanism 85 (see in FIG. 10); and an opticalmicroscope 871 which forms part of an alignment controller 87 foraligning the wafer on the stage device 50.

[0294] The cassette holder 10 is configured to hold a plurality (two inthis embodiment) of cassettes c (for example, closed cassettes such asSMIF,FOUP manufactured by Assist Co.) in which a plurality (for example,25) of wafers are placed side by side in parallel, oriented in thevertical direction. The cassette holder 10 can be arbitrarily selectedfor installation adapted to a particular loading mechanism.Specifically, when a cassette, carried to the cassette holder 10, isautomatically loaded into the cassette holder 10 by a robot or the like,the cassette holder 10 having a structure adapted to the automaticloading can be installed. When a cassette is manually loaded into thecassette holder 10, the cassette holder 10 having an open cassettestructure can be installed.

[0295] In this embodiment, the cassette holder 10 is the type adapted tothe automatic cassette loading, and comprises, for example, an up/downtable 11, and an elevation mechanism 12 for moving the up/down table 11up and down. The cassette c can be automatically set onto the up/downtable 11 in the position indicated by chain lines in FIG. 2. After thesetting, the cassette c is automatically rotated to the positionindicated by solid lines in FIG. 2 so that it is directed to the axis ofpivotal movement of a first carrier unit within the mini-environmentdevice 20. In addition, the up/down table 11 is moved down to theposition indicated by chain lines in FIG. 1. In this way, the cassetteholder 10 for use in automatic loading, or the cassette holder 10 foruse in manual loading may be both implemented by those in knownstructures, so that detailed description on their structures andfunctions are omitted.

[0296] In another embodiment shown in FIG. 3B, a plurality of 300 mmφsubstrates W is accommodated in a slot-like pocket (not shown) fixedlymounted in a box main body 501 so as to be transferred and stored. Thissubstrate carrier box 24 is composed of a box main body 501 of cylinderwith angular section, a door 502 for carrying in/out the substrate,which is coupled with an automatic aperture/closing unit of the door forcarrying in/out the substrate so as to be capable of mechanicallyaperture/closing an aperture in a side face of the box main body 501, alid body 503 disposed in an opposite side of said aperture, for coveringanother aperture through which filters and a fun motor are to beattached or detached, a slot-like pocket (not shown) for holding asubstrate W, a ULPA filter 505, a chemical filter 506, and a fun motor507. In this embodiment, the substrate W is carried in or out by a firstcarrier unit 612 of robot type in a loader 60.

[0297] It should be noted that substrates, i.e., wafers accommodated inthe cassette c are wafers subjected to testing which is generallyperformed after a process for processing the wafers or in the middle ofthe process within semiconductor manufacturing processes. Specifically,accommodated in the cassette are substrates or wafers which haveundergone a deposition process, CMP, ion implantation and so on; waferseach formed with circuit patterns on the surface thereof; or waferswhich have not been formed with wiring patterns. Since a large number ofwafers accommodated in the cassette c are spaced from each other in thevertical direction and arranged side by side in parallel, the firstcarrier unit has an arm which is vertically movable such that a wafer atan arbitrary position can be held by the first carrier unit, asdescribed later in detail.

[0298] In FIGS. 1 through 3, the mini-environment device 20 comprises ahousing 22 which defines a mini-environment space 21 that is controlledfor the atmosphere; a gas circulator 23 for circulating a gas such asclean air within the mini-environment space 21 for the atmospherecontrol; a discharger 24 for recovering a portion of air supplied intothe mini-environment space 21 for discharging; and a pre-aligner 25 forroughly aligning a substrate, i.e., a wafer under testing, which isplaced in the mini-environment space 21.

[0299] The housing 22 has a top wall 221, a bottom wall 222, andperipheral wall 223 which surrounds four sides of the housing 22 toprovide a structure for isolating the mini-environment space 21 from theoutside. For controlling the atmosphere in the mini-environment space21, the gas circulator 23 comprises a gas supply unit 231 attached tothe top wall 221 within the mini-environment space 21 as illustrated inFIG. 3 for cleaning a gas (air in this embodiment) and delivering thecleaned gas downward through one or more gas nozzles (not shown) inlaminar flow; a recovery duct 232 disposed on the bottom wall 222 withinthe mini-environment space for recovering air which has flown down tothe bottom; and a conduit 233 for connecting the recovery duct 232 tothe gas supply unit 231 for returning recovered air to the gas supplyunit 231.

[0300] In this embodiment, the gas supply unit 231 takes about 20% ofair to be supplied, from the outside of the housing 22 for cleaning.However, the percentage of gas taken from the outside may be arbitrarilyselected. The gas supply unit 231 comprises an HEPA or ULPA filter in aknown structure for creating cleaned air. The laminar downflow ofcleaned air is mainly supplied such that the air passes a carryingsurface formed by the first carrier unit, later described, disposedwithin the mini-environment space 21 to prevent dust particles, whichcould be produced by the carrier unit, from attaching to the wafer.

[0301] Therefore, the downflow nozzles need not be positioned near thetop wall as illustrated, but is only required to be above the carryingsurface formed by the carrier unit. In addition, the air need not eitherbe supplied over the entire mini-environment space 21.

[0302] It should be noted that an ion wind may be used as cleaned air toensure the cleanliness as the case may be. Also, a sensor may beprovided within the mini-environment space 21 for observing thecleanliness such that the apparatus is shut down when the cleanliness isdegraded. An access port 225 is formed in a portion of the peripheralwall 223 of the housing 22 that is adjacent to the cassette holder 10. Ashutter device in a known structure may be provided near the access port225 to shut the access port 225 from the mini-environment device 20. Thelaminar downflow near the wafer may be, for example, at a rate of 0.3 to0.4 m/sec. The gas supply unit 231 may be disposed outside themini-environment space 21 instead of within the mini-environment space21.

[0303] The discharger 24 comprises a suction duct 241 disposed at aposition below the wafer carrying surface of the carrier unit and belowthe carrier unit; a blower 242 disposed outside the housing 22; and aconduit 243 for connecting the suction duct 241 to the blower 242. Thedischarger 24 aspires a gas flowing down around the carrier unit andincluding dust, which could be produced by the carrier unit, through thesuction duct 241, and discharges the gas outside the housing 22 throughthe conduits 243, 244 and the blower 242. In this event, the gas may beemitted into an exhaust pipe (not shown) which is laid to the vicinityof the housing 22.

[0304] The aligner 25 disposed within the mini-environment space 21optically or mechanically detects an orientation flat (which refers to aflat portion formed along the outer periphery of a circular wafer)formed on the wafer, or one or more V-shaped notches formed on the outerperipheral edge of the wafer to previously align the position of thewafer in a rotating direction about the axis O₁-O₁ at an accuracy ofapproximately ± one degree. The pre-aligner forms part of a mechanismfor determining the coordinates of an object under testing, which is afeature of the claimed invention, and is responsible for rough alignmentof an object under testing. Since the pre-aligner itself may be of aknown structure, description on its structure and operation is omitted.

[0305] Although not shown, a recovery duct for the discharger 24 mayalso be provided below the pre-aligner such that air including dust,emitted from the pre-aligner, is emitted to the outside.

[0306] In FIGS. 1 and 2, the main housing 30, which defines the workingchamber 31, comprises a housing body 32 that is supported by a housingsupporting device 33 fixed on a vibration isolator 37 disposed on a baseframe 36. The housing supporting device 33 comprises a frame structure331 assembled into a rectangular form. The housing body 32 comprises abottom wall 321 securely fixed on the frame structure 331; a top wall322; and a peripheral wall 323 which is connected to the bottom wall 321and the top wall 322 and surrounds four sides of the housing body 32,and isolates the working chamber 31 from the outside. In thisembodiment, the bottom wall 321 is made of a relatively thick steelplate to prevent distortion due to the weight of equipment carriedthereon such as the stage device 50. Alternatively, another structuremay be employed.

[0307] In this embodiment, the housing body 32 and the housingsupporting device 33 are assembled into a rigid construction, and thevibration isolator 37 prevents vibrations from the floor, on which thebase frame 36 is placed, from being transmitted to the rigid structure.A portion of the peripheral wall 323 of the housing body 32 that adjoinsthe loader housing 40, later described, is formed with an access port325 for introducing and removing a wafer.

[0308] The vibration isolator 37 may be either of an active type whichhas an air spring, a magnetic bearing and so on, or a passive typelikewise having these components. Since any known structure may beemployed for the vibration isolator 37, description on the structure andfunctions of the vibration isolator itself is omitted. The workingchamber 31 is held in a vacuum atmosphere by a vacuum system (not shown)in a known structure. A controller 2 for controlling the operation ofthe overall apparatus is disposed below the base frame 36.

[0309] In FIGS. 1, 2 and 4, the loader housing 40 comprises a housingbody 43 which defines a first loading chamber 41 and a second loadingchamber 42. The housing body 43 comprises a bottom wall 431; a top wall432; a peripheral wall 433 which surrounds four sides of the housingbody 43; and a partition wall 434 for partitioning the first loadingchamber 41 and the second loading chamber 42 such that both the loadingchambers can be isolated from the outside. The partition wall 434 isformed with an aperture, i.e., an access port 435 for passing a waferbetween both the loading chambers. Also, a portion of the peripheralwall 433 that adjoins the mini-environment device 20 and the mainhousing 30 is formed with access ports 436, 437.

[0310] The housing body 43 of the loader housing 40 is carried on andsupported by the frame structure 331 of the housing supporting device33. This prevents the vibrations of the floor from being transmitted tothe loader housing 40 as well. The access port 436 of the loader housing40 is in alignment with the access port 226 of the housing 22 of themini-environment device 20, and a shutter device 27 is provided forselectively isolating a interaction between the mini-environment space21 and the first loading chamber 41. The gate valve 27 has a sealingmaterial 271 which surrounds the peripheries of the access ports 226,436 and is fixed to the side wall 433 in close contact therewith; a door272 for isolating air from flowing through the access ports incooperation with the sealing material 271; and a driver 273 for movingthe door 272.

[0311] Likewise, the access port 437 of the loader housing 40 is inalignment with the access port 325 of the housing body 32, and a shutter45 is provided for selectively isolating a intraction between the secondloading chamber 42 and the working chamber 31 in a hermetic manner. Theshutter 45 comprises a sealing material 451 which surrounds theperipheries of the access ports 437, 325 and is fixed to side walls 433,323 in close contact therewith; a door 452 for isolating air fromflowing through the access ports in cooperation with the sealingmaterial 451; and a driver 453 for moving the door 452.

[0312] Further, the aperture formed through the partition wall 434 isprovided with a shutter 46 for closing the aperture with the door 461 toselectively isolating a interaction between the first and second loadingchambers in a hermetic manner. These gate valve 27, 45, 46 areconfigured to provide air-tight sealing for the respective chambers whenthey are in a closed state. Since these gate valve may be implemented byknown ones, detailed description on their structures and operations isomitted. It should be noted that a method of supporting the housing 22of the mini-environment device 20 is different from a method ofsupporting the loader housing 40. Therefore, for preventing vibrationsfrom being transmitted from the floor through the mini-environmentdevice 20 to the loader housing 40 and the main housing 30, avibration-absorption cushion material may be disposed between thehousing 22 and the loader housing 40 to provide air-tight sealing forthe peripheries of the access ports.

[0313] Within the first loading chamber 41, a wafer rack 47 is disposedfor supporting a plurality (two in this embodiment) of wafers spaced inthe vertical direction and maintained in a horizontal position. Asillustrated in FIG. 5, the wafer rack 47 comprises posts 472 fixed atfour corners of a rectangular substrate 471, spaced from one another, inan upright position. Each of the posts 472 is formed with supportingdevices 473, 474 in two stages, such that peripheral edges of wafers Ware carried on and held by these supporting devices. Then, leading endsof arms of the first and second carrier units, later described, arebrought closer to wafers from adjacent posts and grab the wafers.

[0314] The loading chambers 41, 42 can be controlled for the atmosphereto be maintained in a high vacuum condition (at a pressure of 10⁻⁵ to10⁻⁶ Pa) by a pumping system (not shown) in a known structure includinga vacuum pump, not shown. In this event, the first loading chamber 41may be held in a low vacuum condition as a low vacuum chamber, while thesecond loading chamber 42 may be held in a high vacuum condition as ahigh vacuum chamber, to effectively prevent contamination of wafers. Theemployment of such a structure allows a wafer, which is accommodated inthe loading chamber and is next subjected to the defect testing, to becarried into the working chamber without delay. The employment of such aloading chambers provides for an improved throughput for the defecttesting, and the highest possible vacuum condition around the electronsource which is required to be kept in a high vacuum condition, togetherwith the principle of a multi-beam type electron system, laterdescribed.

[0315] The first and second loading chambers 41, 42 are connected to avacuum exhaust pipe and a vent pipe for an inert gas (for example, driedpure nitrogen) (neither of which are shown), respectively. In this way,the atmospheric state within each loading chamber is attained by aninert gas vent (which injects an inert gas to prevent an oxygen gas andso on other than the inert gas from attaching on the surface). Since anapparatus itself for implementing the inert gas vent is known instructure, detailed description thereon is omitted.

[0316] In the testing apparatus according to the present invention whichuses an electron beam, when representative lanthanum hexaboride (LaB₆)used as an electron source for an electro-optical system, laterdescribed, is once heated to such a high temperature that causesemission of thermal electrons, it should not be exposed to oxygen withinthe limits of possibility so as not to shorten the lifetime. Theexposure to oxygen can be prevented without fail by carrying out theatmosphere control as mentioned above at a stage before introducing awafer into the working chamber in which the electron-optical system isdisposed.

[0317] The stage device 50 comprises a fixed table 51 disposed on thebottom wall 301 of the main housing 30; a Y-table 52 movable in aY-direction on the fixed table 51 (the direction vertical to the drawingsheet in FIG. 1); an X-table 53 movable in an X-direction on the Y-table52 (in the left-to-right direction in FIG. 1); a turntable 54 rotatableon the X-table; and a holder 55 disposed on the turntable 54. A wafer isreleasably held on a wafer carrying surface 551 of the holder 55. Theholder 55 may be of a known structure which is capable of releasablygrabbing a wafer by means of a mechanical or electrostatic chuckfeature.

[0318] The stage device 50 uses servo motors, encoders and a variety ofsensors (not shown) to operate a plurality of tables as mentioned aboveto permit highly accurate alignment of a wafer held on the carryingsurface 551 by the holder 55 in the X-direction, Y-direction andZ-direction (in the up-down direction in FIG. 1) with respect to anelectron beam irradiated from the electro-optical device, and in adirection about the axis normal to the wafer supporting surface (θdirection). The alignment in the Z-direction may be made such that theposition on the carrying surface 551 of the holder 55, for example, canbe finely adjusted in the Z-direction. In this event, a referenceposition on the carrying surface 551 is sensed by a position measuringdevice using a laser of an extremely small diameter (a laserinterference range finder using the principles of interferometer) tocontrol the position by a feedback circuit, not shown. Additionally oralternatively, the position of a notch or an orientation flat of a waferis measured to sense a plane position or a rotational position of thewafer relative to the electron beam to control the position of the waferby rotating the turntable 54 by a stepping motor which can be controlledin extremely small angular increments.

[0319] In order to maximally prevent dust produced within the workingchamber, servo motors 531, 531 and encoders 522, 532 for the stagedevice 50 are disposed outside the main housing 30. Since the stagedevice 50 may be of a known structure used, for example, in steppers andso on, detailed description on its structure and operation is omitted.Likewise, since the laser interference range finder may also be of aknown structure, detailed description on its structure and operation isomitted.

[0320] It is also possible to establish a basis for signals which aregenerated by previously inputting a rotational position, and X-,Y-positions of a wafer relative to the electron beam in a signaldetecting system or an image processing system, later described. Thewafer chucking mechanism provided in the holder 55 is configured toapply a voltage for chucking a wafer to an electrode of an electrostaticchuck, and the alignment is made by pinning three points on the outerperiphery of the wafer (preferably spaced equally in the circumferentialdirection). The wafer chucking mechanism comprises two fixed aligningpins and a push-type clamp pin. The clamp pin can implement automaticchucking and automatic releasing, and constitutes a conducting spot forapplying the voltage.

[0321] While in this embodiment, the X-table is defined as a table whichis movable in the left-to-right direction in FIG. 2; and the Y-table asa table which is movable in the up-down direction, a table movable inthe left-to-right direction in FIG. 2 may be defined as the Y-table; anda table movable in the up-down direction as the X-table.

[0322] The loader 60 comprises a robot-type first carrier unit 61disposed within the housing 22 of the mini-environment device 20; and arobot-type second carrier unit 63 disposed within the second loadingchamber 42. The first carrier unit 61 comprises a multi-node arm 612rotatable about an axis O₁-O₁ with respect to a driver 611. While anarbitrary structure may be used for the multi-node arm, the multi-nodearm in this embodiment has three parts which are pivotably attached toeach other. One part of the arm 612 of the first carrier unit 61, i.e.,the first part closest to the driver 611 is attached to a rotatableshaft 613 by a driving mechanism (not shown) of a known structure,disposed within the driver 611.

[0323] The arm 612 is pivotable about the axis O₁-O₁ by means of theshaft 613, and radially telescopic as a whole with respect to the axisO₁-O₁ through relative rotations among the parts. At a leading end ofthe third part of the arm 612 furthest away from the shaft 613, agrabber 616 in a known structure for grabbing a wafer, such as amechanical chuck or an electrostatic chuck, is disposed. The driver 611is movable in the vertical direction by an elevating mechanism 615 in aknown structure.

[0324] The first carrier unit 61 extends the arm 612 in either adirection M1 or a direction M2 within two cassettes c held in thecassette holder 10, and removes a wafer accommodated in a cassette c bycarrying the wafer on the arm or by grabbing the wafer with the chuck(not shown) attached at the leading end of the arm.

[0325] Subsequently, the arm is retracted (in a position as illustratedin FIG. 2), and then rotated to a position at which the arm can extendin a direction M3 toward the prealigner 25, and stopped at thisposition. Then, the arm is again extended to transfer the wafer held onthe arm to the prealigner 25. After receiving a wafer from theprealigner 25, contrary to the foregoing, the arm is further rotated andstopped at a position at which it can extend to the second loadingchamber 41 (in the direction M3), and transfers the wafer to a waferreceiver 47 within the second loading chamber 41.

[0326] For mechanically grabbing a wafer, the wafer should be grabbed ona peripheral region (in a range of approximately 5 mm from theperipheral edge). This is because the wafer is formed with deviceconstruction (circuit patterns) over the entire surface except for theperipheral region, and grabbing the inner region would result in failedor defective devices.

[0327] The second carrier unit 63 is basically identical to the firstcarrier unit 61 in structure except that the second carrier unit 63carries a wafer between the wafer rack 47 and the carrying surface ofthe stage device 50, so that detailed description thereon is omitted.

[0328] In the loader 60, the first and second carrier units 61, 63 eachcarry a wafer from a cassette held in the cassette holder 10 to thestage device 50 disposed in the working chamber 31 and vice versa, whileremaining substantially in a horizontal position. The arms of thecarrier units are moved in the vertical direction only when a wafer isremoved from and inserted into a cassette, when a wafer is carried onand removed from the wafer rack, and when a wafer is carried on andremoved from the stage device 50. It is therefore possible to smoothlycarry a larger wafer, for example, a wafer having a diameter of 30 cm.Next, how a wafer is carried will be described in sequence from thecassette c held by the cassette holder 10 to the stage device 50disposed in the working chamber 31.

[0329] As described above, when the cassette is manually set, thecassette holder 10 having a structure adapted to the manual setting isused, and when the cassette is automatically set, the cassette holder 10having a structure adapted to the automatic setting is used. In thisembodiment, as the cassette c is set on the up/down table 11 of thecassette holder 10, the up/down table 11 is moved down by the elevatingmechanism 12 to align the cassette c with the access port 225.

[0330] As the cassette is aligned with the access port 225, a cover (notshown) provided for the cassette is opened, and a cylindrical cover isapplied between the cassette c and the access port 225 of themini-environment to block the cassette and the mini-environment space 21from the outside. Since these structures are known, detailed descriptionon their structures and operations is omitted. When the mini-environmentdevice 20 is provided with a shutter for aperture and closing the accessport 225, the shutter is operated to open the access port 225.

[0331] On the other hand, the arm 612 of the first carrier unit 61remains oriented in either the direction M1 or M2 (in the direction M1in this description). As the access port 225 is opened, the arm 612extends to receive one of wafers accommodated in the cassette at theleading end. While the arm and a wafer to be removed from the cassetteare adjusted in the vertical position by moving up or down the driver611 of the first carrier unit 61 and the arm 612 in this embodiment, theadjustment may be made by moving up and down the up/down table 11 of thecassette holder 10, or made by both.

[0332] As the arm 612 has received the wafer, the arm 621 is retracted,and the shutter is operated to close the access port (when the shutteris provided). Next, the arm 612 is pivoted about the axis O₁-O₁ suchthat it can extend in the direction M3. Then, the arm 612 is extendedand transfers the wafer carried at the leading end or grabbed by thechuck onto the prealigner 25 which aligns the orientation of therotating direction of the wafer (the direction about the central axisvertical to the wafer plane) within a predetermined range. Uponcompletion of the alignment, the carrier unit 61 retracts the arm 612after a wafer has been received from the prealigner 25 to the leadingend of the arm 612, and takes a posture in which the arm 612 can beextended in a direction M4. Then, the door 272 of the gate valve 27 ismoved to open the access ports 223, 236, and the arm 612 is extended toplace the wafer on the upper stage or the lower stage of the wafer rack47 within the first loading chamber 41. It should be noted that beforethe shutter device 27 opens the access ports to transfer the wafer tothe wafer rack 47, the aperture 435 formed through the partition wall434 is closed by the door 461 of the shutter 46 in an air-tight state.

[0333] In the process of carrying a wafer by the first carrier unit,clean air flows (as downflow) in laminar flow from the gas supply unit231 disposed on the housing of the mini-environment device to preventdust from attaching on the upper surface of the wafer during thecarriage. A portion of the air near the carrier unit (in thisembodiment, about 20% of the air supplied from the supply unit 231,mainly contaminated air) is aspired from the suction duct 241 of thedischarger 24 and emitted outside the housing. The remaining air isrecovered through the recovery duct 232 disposed on the bottom of thehousing and returned again to the gas supply unit 231.

[0334] As the wafer is placed into the wafer rack 47 within the firstloading chamber 41 of the loader housing 40 by the first carrier unit61, the shutter device 27 is closed to seal the loading chamber 41.Then, the first loading chamber 41 is filled with an inert gas to expelair. Subsequently, the inert gas is also evacuated so that a vacuumatmosphere dominates within the loading chamber 41.

[0335] The vacuum atmosphere within the loading chamber 41 may be at alow vacuum degree. When a certain degree of vacuum is provided withinthe loading chamber 41, the shutter 46 is operated to open the accessport 434 which has been sealed by the door 461, and the arm 632 of thesecond carrier unit 63 is extended to receive one wafer from the waferreceiver 47 with the grabber at the leading end (the wafer is carried onthe leading end or grabbed by the chuck attached to the leading end).Upon completion of the receipt of the wafer, the arm 632 is retracted,followed by the shutter 46 again operated to close the access port 435by the door 461. It should be noted that the arm 632 has previouslytaken a posture in which it can extend in the direction N1 of the waferrack 47 before the shutter 46 is operated to open the access port 435.

[0336] Also, as described above, the access ports 437, 325 have beenclosed by the door 452 of the shutter 45 before the shutter 46 isoperated to block the interaction between the second loading chamber 42and the working chamber 31 in an air-tight condition, so that the secondloading chamber 42 is evacuated.

[0337] As the shutter 46 is operated to close the access port 435, thesecond loading chamber 42 is again evacuated at a higher degree ofvacuum than the first loading chamber 41. Meanwhile, the arm 632 of thesecond carrier unit 63 is rotated to a position at which it can extendtoward the stage device 50 within the working chamber 31. On the otherhand, in the stage device 50 within the working chamber 31, the Y-table52 is moved upward, as viewed in FIG. 2, to a position at which thecenter line O₀-O₀ of the X-table 53 substantially matches an X-axisX₁-X₁ which passes a pivotal axis O₂-O₂ of the second carrier unit 63.The X-table 53 in turn is moved to the position closest to the leftmostposition in FIG. 2, and remains awaiting at this position.

[0338] When the second loading chamber 42 is evacuated to substantiallythe same degree of vacuum as the working chamber 31, the door 452 of thegate valve 45 is moved to open the access ports 437, 325, allowing thearm 632 to extend so that the leading end of the arm 632, which holds awafer, approaches the stage device 50 within the working chamber 31.Then, the wafer is placed on the carrying surface 551 of the stagedevice 50. As the wafer has been placed on the carrying surface 551, thearm 632 is retracted, followed by the shutter 45 operated to close theaccess ports 437, 325.

[0339] The foregoing description has been made on the operation until awafer in the cassette c is carried and placed on the stage device 50.For returning a wafer, which has been carried on the stage device 50 andprocessed, from the stage device 50 to the cassette c, the operationreverse to the foregoing is performed. Since a plurality of wafers arestored in the wafer rack 47, the first carrier unit 61 can carry a waferbetween the cassette and the wafer rack 47 while the second carrier unit63 is carrying a wafer between the wafer rack 47 and the stage device50, so that the testing operation can be efficiently carried out.

[0340] In specific, when there are a wafer A, which has been alreadyprocessed, and a wafer B, which has not yet been processed, in a waferrack 47 of a second carrier unit, at first, the wafer B which has notyet been processed is transferred to the stage 50 and the processing isstarted. During this processing, the wafer A which has already beenprocessed is transferred from the stage 50 to the wafer rack 47 by anarm, a wafer C which has not yet been processed is picked up from thewafer rack 47 again by the arm, which after having been positioned by apre-aligner, is further transferred to the wafer rack 47 of a loadingchamber 41.

[0341] This procedure may allow, in the wafer rack 47, the wafer A whichhas already been processed to be substituted by the wafer C which hasnot yet been processed, during the wafer B being processed.

[0342] Alternatively, depending on the way how to use such an apparatusfor executing an inspection and/or an evaluation, a plurality of stageunits 50 may be arranged in parallel, so that the wafers may betransferred from one wafer rack 47 to each of the stage units 50 therebyapplying a similar processing to a plurality of wafers.

[0343]FIGS. 6A, 6B illustrate exemplary modifications to the method ofsupporting the main housing 30. In an exemplary modification illustratedin FIG. 6A, a housing supporting device 33 a is made of a thickrectangular steel plate 331 a, and a housing body 32 a is placed on thesteel plate. Therefore, the bottom wall 321 a of the housing body 32 ais thinner than the bottom wall 222 of the housing body 32 in theforegoing embodiment. In an exemplary modification illustrated in FIG.6B, a housing body 32 b and a loader housing 40 b are suspended by aframe structure 336 b of a housing supporting device 33 b. Lower ends ofa plurality of vertical frames 337 b fixed to the frame structure 336 bare fixed to four corners of a bottom wall 321 b of the housing body 32b, such that the peripheral wall and the top wall are supported by thebottom wall. Then, a vibration isolator 37 b is disposed between theframe structure 336 b and a base frame 36 b.

[0344] Likewise, the loader housing 40 is suspended by a suspendingmember 49 b fixed to the frame structure 336. In the exemplarymodification of the housing body 32 b illustrated in FIG. 6B, thehousing body 32 b is supported in suspension, the general center ofgravity of the main housing and a variety of devices disposed thereincan be brought downward. The methods of supporting the main housing andthe loader housing, including the exemplary modifications describedabove, are configured to prevent vibrations from being transmitted fromthe floor to the main housing and the loader housing.

[0345] In another exemplary modification, not shown, the housing body ofthe main housing is only supported by the housing supporting device frombelow, while the loader housing may be placed on the floor in the sameway as the adjacent mini-environment device. Alternatively, in a furtherexemplary modification, not shown, the housing body of the main housingis only supported by the frame structure in suspension, while the loaderhousing may be placed on the floor in the same way as the adjacentmini-environment device.

[0346] An electron optical apparatus 70 (first embodiment in FIG. 1)comprises a lens column 71 fixedly mounted to a housing 32, said lenscolumn containing an electron optical system therein comprising aprimary electron optical system 72 (hereafter referred to as a primaryoptical system for simplicity) and a secondary electron optical system74 (hereafter referred to as a secondary optical system for simplicity),and a detecting system 76, as schematically illustrated in FIGS. 7 and8.

[0347] The primary optical system 72 is such an optical system thatirradiates an electron beam against a top surface of a wafer W beinginspected, and comprises an electron gun 721 for emitting an electronbeam, an electrostatic lens or a condenser lens 722 for converging theprimary electron beam emitted from the electron gun 721, amulti-aperture plate 723 disposed beneath the condenser lens 722 andhaving a plurality of apertures formed therethrough for forming theprimary electron beam into a plurality of electron beams or amulti-beam, an electrostatic lens or a demagnifying lens 724 fordemagnifying the primary electron beams, a Wien filter or an E×Bseparator 725, and an objective lens 726, which are sequentiallyarranged with the electron gun 721 in the topmost level as shown in FIG.7 so that an optical axis of the primary electron beam emitted from theelectron gun should be normal with respect to the surface of an object Sto be inspected.

[0348] In order to remove a negative effect of field curvatureaberration by the demagnifying lens 724 and the objective lens 726, aplurality of small apertures 723 a (nine apertures in this embodiment)is arranged on the multi-aperture plate 723 so as to be located in aconcentric circular configuration with the optical axis, as shown inFIG. 8, such that a space Lx between the projections of the apertures inthe X direction is equal to one another.

[0349] The secondary optical system 74 comprises magnifying lenses 741and 742 forming a unit of two-stage electrostatic lenses which allowssecondary electrons separated from the primary optical system by the E×Btype deflecting system (E×B filter) 724 to pass therethrough, and alsocomprises a multi-aperture detection plate 743. A plurality of apertures743 a formed through the multi-aperture detection plate 743 correspondsto the plurality of apertures 723 a formed through the multi-apertureplate 723 in the primary optical system on one to one basis.

[0350] The detecting system 76 comprises a plurality of detectors 761(nine detectors in this embodiment) disposed adjacently to themulti-aperture detection plate 743 in the secondary optical system 74 soas for each of them to correspond respectively to each of the apertures743 a, and also an image processing section 763 electrically connectedto each of the detectors 761 via an A/D converter 762.

[0351] An operation of the electro optical apparatus (second embodimentin FIG. 7) with an above configuration will now be described. Theprimary electron beam emitted from the electron gun 721 is converged bythe condenser lens 722 in the primary optical system 72 to form acrossover at a point P1. On the other hand, the primary electron beamconverged by the condenser lens 722 passes through the plurality ofapertures 723 a of the multi-aperture plate to form into a plurality ofprimary electron beams, which are contracted by the minifying lens 724so as to be projected onto a point P2. After being focused onto thepoint P2, the beams are further focused onto a surface of a wafer W bythe objective lens 726. On the other hand, the deflecting system 727disposed between the minifying lens 724 and the objective lens 726deflects the primary electron beams so as to scan the surface of thewafer W.

[0352] The plurality of focused primary electron beams (nine beams inthis embodiment) is irradiated onto the sample S at a plurality ofpoints thereon, and secondary electrons are emanated from said pluralityof points. Those secondary electrons are attracted by an electric fieldof the objective lens 726 to be converged narrower, and then deflectedby the E×B separator 725 so as to be introduced into the secondaryoptical system 74. The secondary electron image is focused on a point P3which is much closer to the deflector 725 than the point P2. This isbecause the primary electron beam has the energy of 500 eV on thesurface of the wafer, while the secondary electron beam only has theenergy of a few eV.

[0353] Each of the images of the secondary electrons focused at thepoint P3 is focused by the two-stage magnifying lenses 741 and 742 ontoeach of the corresponding apertures 743 a of the multi-aperturedetection plate 743 to be formed into an image, so that each of thedetectors 761 disposed correspondingly to each of the apertures 743 adetects the image. Each of the detectors 761 thus detects the electronbeam and converts it into an electric signal representative of itsintensity. The generated electric signals are output from respectivedetectors 761, and after being converted respectively into digitalsignals by the A/D converter 762, they are input to the image processingsection 763.

[0354] The image processing section 763 converts the input digitalsignals into image data. Since the image processing section 763 isfurther supplied with a scanning signal for deflecting the primaryelectron beam, the image processing section 763 can display an imagerepresenting the surface of the wafer. Comparing this image with areference pattern that has been pre-set in a setting device (not shown)allows to determine whether or not the pattern on the wafer W beinginspected (evaluated) is acceptable. Further, the line width of thepattern formed on the surface of the wafer W can be measured in such away that the pattern to be measured on the wafer W is moved by aregistration to the proximity of the optical axis of the primary opticalsystem, and the pattern is then line-scanned to extract the line widthevaluation signal, which in turn is appropriately calibrated.

[0355] In this regard, it is required to make special arrangements inorder to minimize the affection by the three aberrations, i.e., thedistortion caused by the primary optical system, the axial chromaticaberration, and the filed astigmatism, when the primary electron beamspassed through the apertures of the multi-aperture plate 723 in theprimary optical system are focused onto the surface of the wafer W andthen the secondary electrons emanated from the wafer W are formed intoan image on the detector 761.

[0356] It is to be noticed that, with respect to the relationshipbetween the spacing of a plurality of primary electron beams and thesecondary optical system, any space between the primary electron beamsmade longer than the aberration by the secondary optical system mayeliminate the cross talks among the plurality of beams.

[0357] As shown in FIG. 1, a pre-charge unit 81 is disposed in a workingchamber 31, adjacent to a lens column 71 of an electronic opticalapparatus 70. Since this inspection apparatus is of a type in which anelectron beam is used to scan and irradiate a substrate to be inspectedor a wafer, and thereby a device pattern or the like formed on a surfaceof the wafer is inspected, information such as secondary electronsemitted by the irradiation of the electron beam is utilized as aninformation of the wafer surface, and sometimes, depending on acondition including a material of the wafer, an energy level of theirradiated electron or the like, the wafer surface may be charged-up.

[0358] Further, depending on the locations on the wafer, some locationsmight be more strongly charged-up than other locations. If there arenon-uniform distribution in a charging amount on the wafer, theinformation of the secondary electron beam is made to be non-uniform,which makes it impossible to obtain an accurate information.

[0359] Accordingly, in the present embodiment, there is provided apre-charge unit 81 having a charged particle irradiating section 811 inorder to prevent this non-uniform distribution. In order to prevent anon-uniform distribution in charging, before the electrons forinspection being irradiated onto a predetermined location of the waferto be inspected, the charged particles are irradiated from the chargedparticle irradiating section 811 of the pre-charge unit thereto, thuspreventing the non-uniform charging. The charging on the wafer surfaceis detected by forming and evaluating an image of the wafer surface inadvance, and based on a result of the detection, the pre-charge unit 81is operated. Further, in this pre-charge unit, the primary electron beammay be irradiated with some gradation.

[0360] Referring next to FIG. 9, the potential applying mechanism 83applies a potential of several kilo volts to a carrier of a stage, onwhich the wafer is placed, to control the generation of secondaryelectrons based on the fact that the information on the secondaryelectrons emitted from the wafer (secondary electron yield) depend onthe potential on the wafer. The potential applying mechanism 83 alsoserves to decelerate the energy originally possessed by irradiatedelectrons to provide the wafer with irradiated electron energy ofapproximately 100 to 500 eV.

[0361] As illustrated in FIG. 9, the potential applying mechanism 83comprises a voltage applying device 831 electrically connected to thecarrying surface 541 of the stage device 50; and a chargingdetection/voltage determining system (hereinafter detection/determiningsystem) 832. The detection/determining system 832 comprises a monitor833 electrically connected to an image forming unit 763 of the detectingsystem 76 in the electro-optical device 70; an operator 834 connected tothe monitor 833; and a CPU 835 connected to the operator 834. The CPU835 supplies a signal to the voltage applying device 831. The potentialapplying mechanism 83 is designed to find a potential at which the waferunder testing is hardly charged, and to apply such potential to thecarrying surface 541.

[0362] As for a method for inspecting for an electric defect on a sampleto be inspected, the defect on the portion which is designed to beelectrically insulated can be detected based on the fact that there is avoltage difference therein between the normal case where the portionbeing insulated and the defective case where the portion being underconductive condition. In this method, at first the electric charges isapplied to the sample in advance, so that the voltage difference isgenerated between the voltage in the portion essentially insulatedelectrically and the voltage in another portion which is designed to beelectrically insulated but is under conductive condition because of anydefective reason, then the beam of the present invention is appliedthereto to obtain a data with voltage difference, which is then analyzedto detect the conductive condition.

[0363] Referring next to FIG. 10, the electron beam calibrationmechanism 85 comprises a plurality of Faraday cups 851, 852 formeasuring a beam current, disposed at a plurality of positions in alateral region of the wafer carrying surface 541 on the turntable 54.The Faraday cuts 851 is used for a fine beam (approximately φ 2 μm),while the Faraday cups 852 is used for total beams (approximately φ 30μm). The Faraday cups 851 for a fine beam measures a beam profile bydriving the turntable, while the Faraday cups 852 for a wide beammeasure a total amount of currents. The Faraday cups 851, 852 aremounted on the wafer carrying surface 541 such that their top surfacesare coplanar with the upper surface of the wafer W carried on thecarrying surface 541. In this way, the primary electron beam emittedfrom the electron gun 721 is monitored at all times. This is because theelectron gun 721 cannot emit a constant electron beam at all times butvaries in the emitting amount as it is used over time.

[0364] The alignment controller 87, which aligns the wafer W with theelectron-optical system 70 using the stage system 50, performs thecontrol for rough alignment through wide field observation using theoptical microscope 871 (a measurement with a lower magnification than ameasurement made by the electron-optical system); high magnificationalignment using the electron-optical system of the electron-opticalsystem 70; focus adjustment; testing region setting; pattern alignment;and so on. The wafer is tested at a low magnification using the opticalsystem in this way because an alignment mark must be readily detected byan electron beam when the wafer is aligned by observing patterns on thewafer in a narrow field using the electron beam for automaticallytesting the wafer for patterns thereon.

[0365] The optical microscope 871 is disposed on the housing 30(alternatively, may be movably disposed within the housing 30), with alight source, not shown, being additionally disposed within the housing30 for operating the optical microscope. The electron-optical system forobserving the wafer at a high magnification shares the electron-opticalsystems (primary optical system 72 and secondary optical system 74) ofthe electron-optical system 70. The configuration may be generallyillustrated in FIG. 10. For observing a point of interest on a wafer ata low magnification, the X-stage 53 of the stage device 50 is moved inthe X-direction to move the point of interest on the wafer into a viewfield of the optical microscope 871. The wafer is viewed in a wide fieldby the optical microscope 871, and the point of interest on the wafer tobe observed is displayed on a monitor 873 through a CCD 872 to roughlydetermine a position to be observed. In this event, the magnification ofthe optical microscope may be changed from a low magnification to a highmagnification.

[0366] Next, the stage device 50 is moved by a distance corresponding toa spacing δx between the optical axis of the electron-optical system 70and the optical axis of the optical microscope 871 to move the point onthe wafer under observation, previously determined by the opticalmicroscope 871, to a point in the view field of the electron-opticaldevice 70.

[0367] The distance δx between the axis O₃-O₃ of the electron-opticaldevice and the axis O₄-O₄ of the optical microscope 871 is previouslyknown (while it is assumed that the electron-optical system 70 isdeviated from the optical microscope 871 in the direction along theX-axis in this embodiment, they may be deviated in the Y-axis directionas well as in the X-axis direction), such that the point underobservation can be moved to the viewing position by moving the stagedevice 50 by the distance δx. The point under observation has been movedto the viewing position of the electron-optical device 70, the pointunder observation is imaged by the electron-optical system at a highmagnification for storing a resulting image or displaying the image onthe monitor 765 through the CCD 761.

[0368] After the point under observation on the wafer imaged by theelectron-optical system at a high magnification is displayed on themonitor 765, misalignment of the stage device 50 with respect to thecenter of rotation of the turntable 54 in the wafer rotating direction,and misalignment δθ of the stage device 50 with respect to the opticalaxis O₃-O₃ of the electron-optical system in the wafer rotatingdirection are detected in a known method, and misalignment of apredetermined pattern with respect to the electron-optical device in theX-axis and Y-axis is also detected. Then, the operation of the stagedevice 50 is controlled to align the wafer based on the detected valuesand data on a testing mark attached on the wafer or data on the shape ofthe patterns on the wafer which have been acquired in separation.

[0369] Next, an embodiment of a method of manufacturing a semiconductordevice according to the present invention will be described withreference to FIGS. 12 and 13.

[0370]FIG. 12 is a flow chart illustrating an embodiment of a method ofmanufacturing a semiconductor device according to the present invention.Manufacturing processes of this embodiment include the following mainprocesses:

[0371] (1) a wafer manufacturing process for manufacturing a wafer (or awafer preparing process for preparing a wafer);

[0372] (2) a mask manufacturing process for manufacturing masks for usein exposure (or mask preparing process for preparing masks);

[0373] (3) a wafer processing process for performing processing requiredto the wafer;

[0374] (4) a chip assembling process for dicing one by one chips formedon the wafer and making them operable; and

[0375] (5) a chip testing process for testing complete chips.

[0376] The respective main processes are further comprised of severalsub-processes.

[0377] Among these main processes, the wafer fabricating process setforth in (3) exerts critical affections to the performance of resultingsemiconductor devices. This process involves sequentially laminatingdesigned circuit patterns on the wafer to form a large number of chipswhich operate as memories, MPUs and so on. The wafer fabricating processincludes the following sub-processes:

[0378] (A) a thin film forming sub-process for forming dielectric thinfilms serving as insulating layers, metal thin films for forming wiringsor electrodes, and so on (using CVD, sputtering and so on);

[0379] (B) an oxidation sub-process for oxidizing the thin film layersand the wafer substrate;

[0380] (C) a lithography sub-process for forming a resist pattern usingmasks (reticles) for selectively fabricating the thin film layers andthe wafer substrate;

[0381] (D) an etching sub-process for fabricating the thin film layersand the substrate in conformity to the resist pattern (using, forexample, dry etching techniques);

[0382] (E) an ion/impurity inplantation/diffusion sub-process;

[0383] (F) a resist striping sub-process; and

[0384] (G) a sub-process for testing the fabricated wafer;

[0385] As appreciated, the wafer fabrication process is repeated anumber of times equal to the number of required layers to manufacturesemiconductor devices which operate as designed.

[0386]FIG. 13 is a flow chart illustrating the lithography sub-processwhich forms the core of the wafer processing process in FIG. 12. Thelithography sub-process includes the following steps:

[0387] (a) a resist coating step for coating a resist on the wafer onwhich circuit patterns have been formed in the previous process;

[0388] (b) a resist exposing step;

[0389] (c) a developing step for developing the exposed resist toproduce a resist pattern; and

[0390] (d) an annealing step for stabilizing the developed resistpattern.

[0391] Since the aforementioned semiconductor device manufacturingprocess, wafer fabrication process and lithography process are wellknown, and therefore no further description will be required.

[0392] When the defect testing method and defect testing apparatusaccording to the present invention are used in the testing sub-processset forth in (G), any semiconductor devices even having submicron(sized) patterns can be tested at a high throughput, so that a totalinspection can also be conducted, thereby making it possible to improvethe yield rate of products and prevent defective products from beingshipped.

[0393] The present invention provides the following effects:

[0394] (a) Since the present invention has allowed the functionalcombination of the respective components of the inspection apparatususing a plurality of electron beams or a multi-beam, the apparatus mayhandle any objects to be inspected with high throughput;

[0395] (b) Arranging a sensor in the environmental space for observingthe cleanness level allows to inspect the object to be inspected undermonitoring dirt (or particle) within the space; and

[0396] (c) Since a pre-charge unit has been arranged, even those wafersmade of insulating materials are hardly affected by the electricdischarge.

[0397]FIG. 14A is a schematic diagram of an optical system in anelectron beam apparatus 1000 of a third embodiment according to thepresent invention. Primary electron beams emitted from multiple emitters1001, 1002 and 1003 are converged by a condenser lens 1004 to beprojected onto an image field 1005, which are further converged by alens 1006 and an objective lens 1008 to be contracted and projected ontoa sample surface 1010. Although FIG. 14A has illustrated only one row ofmultiple emitters, plural rows of emitters may be arranged as shown inFIG. 17A.

[0398]FIG. 17A shows emitters in the array of 3×3, and FIG. 17B is across sectional view taken along the line 17B-17B of FIG. 17A. In FIGS.17A and 17B, reference numeral 1021 designates a Si substrate, 1022 is aMo emitter, 1023 is an Au leading electrode, and 1024 is a Si₃N₄insulating film. The number of emitters may be chosen appropriately. Alens unit has been constructed with a few numbers of planar electrodeseach having an aperture with a diameter of 2 to 10 μm and having beenaligned in the optical axial direction with the interval of 2 to 10 μmtherebetween and have different voltages applied thereto, so that it mayoperates as a convex lens.

[0399] Secondary electrons emanated from the sample surface 1010 whichhas been irradiated with the primary electron beam delivered from themultiple emitters 1001, 1002 and 1003 are accelerated by an acceleratingelectric field applied between the sample surface 1010 and the objectivelens 1008, and even the secondary electrons emitted at a great emissionangle may be converged narrower by the time when they enter into theobjective lens 1008, which further pass through an aperture diaphragm1007 to be formed into an image by the lens 1006 on the same image field1005 as of the primary beams.

[0400] An E×B separator 1009 is arranged at the location of the imagefield 1005 so as to separate the secondary electrons passed through thelens 1006 from the primary optical system. The E×B separator 1009 hassuch a configuration in which an electric field and a magnetic field arecrossed at a right angle within a plane orthogonal to the normal of thesample surface 1010 (the upper direction on paper), and the relationshipbetween the electric field, the magnetic field and the primary electronenergy has been established to allow the primary electrons to beadvanced straight forward.

[0401] The separated secondary electrons are optically magnified withlenses 1011 and 1012 so as to be formed into a plurality of images on adetection system 1013. The detection system 1013 is provided withdetectors 1014, 1015 and 1016 corresponding respectively to the primaryelectron beams from the multiple emitters 1001, 1002 and 1003, each ofwhich detects the secondary electrons emanated from the surface of thesample which has been irradiated with each of those electron beams. Itis to be noted that the multiple emitters 1001, 1002 and 1003 arearranged such that they are slightly offset to one another in the Z-axisdirection in order to compensate for the image field curvature of theprimary optical system. That is, the emitter 1001 on the optical axis isarranged at the farthest location from the sample, the emitter 1002distant from the optical axis is displaced to be closer to the sample incomparison with the location of the emitter 1001 by the valuecorresponding to the field curvature, and the emitter 1003 more distantfrom the optical axis is displaced to be much closer to the sample.

[0402] To irradiate overall surface of the sample, the primary electronbeams from the multiple emitters are controlled to make a scanningmotion by an electrostatic deflecting system 1017. Further, insynchronism with the scanning motion of the primary electron beams,another electrostatic deflecting system 1018 arranged in the secondaryoptical system also controls the motion of the secondary electrons so asto enter always into the specified detectors 1014, 1015 and 1016regardless of their scanning position.

[0403] That is, the secondary electrons emanated by the primary electronbeams from the emitters 1001, 1002 and 1003 are controlled to enterrespectively into the detectors 1014, 1015 and 1016. The detectors takethe form of electrodes arranged on a curved surface having the samenumber of apertures as that of the detectors formed in front of a PINdiode with the voltage of about 20 kV applied thereto, and the voltageof about 1 kV is applied to this electrode. The convex lens effect ofthe electric field produced by the voltage of 20 kV leaking from thoseapertures affects all of the secondary electrons approaching to thevicinity of those apertures so as to go through the apertures into thedetectors. The curved surface has such a shape that can compensate forthe field curvature of the secondary optical system.

[0404] Now, a relationship between the spacing of the irradiatingpositions of the plurality of primary electron beams and the secondaryoptical system will be described. FIG. 15 shows the secondary opticalsystem and an angular aperture. As shown in FIG. 15, it is assumed thatthe secondary electrons within the acceptance angle al go through theobjective lens 1008, the diaphragm 1007 and the lens 1006 to be imagedon the image field 1005. At that time, a half-angular aperture at theimage field 1005 is αi, and apparent angles α0 and αi viewed from theobjective lens 1008 will be defined as αi/α0=1/M, where themagnification for the secondary optical system is M. Further, the anglesα0 and αi will be also defined as (α1/α0)2=V8/Vini, where the beampotential at the objective lens 1008 is V8 and the initial energy of thesecondary electron is Vini.

[0405]FIG. 16 shows the relationship between the aberration at thesurface of the sample 1010 and the half-angular aperture αi. In FIG. 16,δS is defined as a spherical aberration, δcoma as a coma aberration, δCas a chromatic aberration and δtotal as the total of them.

[0406] Now, for the acceptance of 20 μm of aberration, the half-angularaperture αi should be equal to or smaller than 5.3 mrad. Further, theinitial energy Vini of the secondary electron to be inspected issufficient to be considered as much as 0.1 eV to 10 eV, so that when themagnification M is assumed to be 5 and the beam potential V8 at theobjective lens 1008 to be 20 kV, the relationship will be denoted asα1=1185 mrad=67.9°.

[0407] Since it has been found that less than 90% of the secondaryelectrons can be taken in for the acceptance angle of 0° to 60° (see,for example, FIG. 6 in the specification of the U.S. Pat. No.5,412,210), therefore for the half-angular aperture αi or the resolutionof the secondary optical system of around 5.3 mrad and the size of thedetector being about four times of 20 μm in the conversion for thesample surface, not less than 90% of the secondary electrons can becollected without any cross talks. Further, the spacing between themultiple emitters being around 100 μm can reduce the cross talks amongthe emitters to be negligible lam level.

[0408] If there is no need to collect not less than 90% of the secondaryelectrons but the collection of 50% of the secondary electronsguarantees the sufficient S/N ratio to be obtained, then the secondaryelectrons emanated within an angle smaller than 45° may be sufficient tobe collected into the detectors. This is because an collectingefficiency of the secondary electrons, η, is denoted by [equation 1] asfollows:

η=∫₀ ^(45°)sinθcosθdθ/∫₀ ^(90°)sinθcosθdθ=0.5

[0409] Thus, respective primary electron beams are irradiated onrespective locations such that a distance between any locations may beapart more than that for the resolution of the secondary optical system.FIG. 14B is an enlarged top plan view of an electron beam irradiationplane, wherein a distance N represents the resolution converted to thedistance on the sample after having passed through lenses 1008, 1011 and1012. In FIG. 14B, the distance N being equal to or longer than adistance between distinguishable two points allows to obtain amulti-beam without cross-talk and also allows to accomplish highthroughput. The electron beam apparatus configured as described abovecan be used for defect inspection of semiconductor and for measurementof micro-distance.

[0410] If the electron beam apparatus of FIG. 14A is used in the chipinspection process according to the flow chart illustrative of anexemplary method for manufacturing a semiconductor device as shown inFIGS. 12 and 13, the inspection with higher throughput or even a hundredpercent inspection may be attained while allowing the yield of theproducts to be improved and preventing any faulty products from beingdelivered.

[0411] As apparent from the above description, according to the electronbeam apparatus of FIG. 14, since almost all of the secondary chargedparticles emanated from the sample can be detected without generatingany cross talks, the defect inspection or the pattern line widthmeasurement with higher S/N ratio can be attained successfully.

[0412] Further, since the aberration of the secondary optical system ofabout 20 μm on the sample surface also provides a satisfied detectionresult, the secondary optical system may not necessarily be of highprecision, while the primary optical system orthogonal to the samplerequires the formation of a plurality of charged particle beams to be ofhigh precision.

[0413] Still further, since between the sample surface and the firststage of lens in the secondary optical system, there has been applied adecelerating electric field with respect to the primary optical systemor an accelerating electric field with respect to the secondary opticalsystem, the primary charged particle beams are more easily converged andalso the secondary charged particles emanated over the wide angle rangeare more easily formed into a narrower bundle of particles at theposition of the first stage of lens so as to be detected efficiently, sothat a signal with better S/N ratio can be obtained and also theaccuracy in measurement can be improved.

[0414]FIGS. 18A and 18B are cross sectional views of a vacuum chamberand an XY stage of a charged beam apparatus according to the prior art,FIG. 19 is a perspective view of a conventional exhaust gas dischargingmechanism used for the XY stage of FIGS. 18A and 18B, FIGS. 20A and 20Bare cross sectional views of a vacuum chamber and an XY stage of acharged beam apparatus (stages etc.) 2000 of a fourth embodimentaccording to the present invention, FIG. 21 is a cross sectional view ofa vacuum chamber and an XY stage of a charged beam apparatus (stagesetc.) 2100 of a fifth embodiment according to the present invention.

[0415]FIG. 22 is a cross sectional view of a vacuum chamber and an XYstage of a charged beam apparatus (stages etc.) 2200 of a sixthembodiment according to the present invention, FIG. 23 is a crosssectional view of a vacuum chamber and an XY stage of a charged beamapparatus (stages etc.) 2300 of a seventh embodiment according to thepresent invention, FIG. 24 is a cross sectional view of a vacuum chamberand an XY stage of a charged beam apparatus (stages etc.) 2400 of aneighth embodiment according to the present invention. In FIGS. 18-24,the similar reference numerals are used to designate the components incommon.

[0416]FIGS. 20A and 20B show a charged beam apparatus of a fourthembodiment of the present invention. A division plate 2014 is attachedonto an upper face of a Y directionally movable unit 2005 of a stage2003, wherein said division plate 2014 overhangs to a great degreeapproximately horizontally in the +Y direction and the −Y direction (thelateral direction in FIG. 20B), so that between an upper face of an Xdirectionally movable unit 2006 and said division plate 2014 may bealways provided a narrow gap 2050 with small conductance therebetween.Also, a similar division plate 2012 is attached onto the upper face ofthe X directionally movable unit 2006 so as to overhang in the ± Xdirection (the lateral direction in FIG. 20A), so that a narrow gap 2051may be constantly formed between an upper face of a stage table 2007 andsaid division plate 2012. The stage table 2007 is fixedly secured onto abottom wall within a housing 2008 with a known method.

[0417] In this way, since the narrow gaps 2050 and 2051 are constantlyformed wherever the sample table 2004 may move to, and the gaps 2050 and2051 can prevent the movement of a desorbed gas even if a gas isdesorbed or leaked along the guiding plane 2006 a or 2007 a uponmovement of the movable unit 2005 or 2006, a pressure increase can besignificantly controlled to low level in a space 2024 adjacent to thesample to which the charged beam is irradiated.

[0418] Since in a side face and an under face of the movable unit 2005and also in an under face of the movable unit 2006 of the stage 2003,there are provided grooves for differential pumping formed surroundinghydrostatic bearings 2009, as shown in FIG. 19, which work forvacuum-pumping, therefore in a case where narrow gaps 2050 and 2051 havebeen formed, the emitted gas from the guiding planes is mainly evacuatedby those differential pumping sections. Owing to this, the pressure inthose spaces 2013 and 2015 within the stage are kept to be higher levelthan the pressure within a chamber C.

[0419] Accordingly, if there are more portions provided forvacuum-pumping the spaces 2013 and 2015 in addition to the differentialpumping grooves 2017 and 2018, the pressure within the spaces 2013 and2015 can be decreased, and the pressure rise of the space 2024 in thevicinity of the sample can be controlled to be further low. For thispurpose, vacuum pumping channels 2011-1 and 2011-2 are provided. Thevacuum pumping channel 2011-1 extends through the stage table 2007 andthe housing 2008 to interact with an outside of the housing 2008. On theother hand, the pumping channel 2011-2 is formed in the X directionallymovable unit 2006 and opened in an under face thereof.

[0420] It is to be noted that though arranging the division plates 2012and 2014 might cause a problem requiring the chamber C to be extended soas not to interfere with the division plates, this can be improved byemploying those division plates of stretchable material or structure.There may be suggested one embodiment in this regard, which employs thedivision plates made of rubber or in a form of bellows, and the endsportions thereof in the direction of movement are fixedly securedrespectively, so that each end of the division plate 2014 is secured tothe X directionally movable unit 2006 and that of the division plate2012 to the inner wall of the housing 2008.

[0421]FIG. 21 shows a charged beam apparatus of a fifth embodiment ofthe present invention. In the fifth embodiment, a cylindrical divider2016 is disposed surrounding the tip portion of the lens column or thecharged beam irradiating section 2002, so that a narrow gap may beproduced between an upper face of a sample S and the tip portion of thelens column. In such configuration, even if the gas is emitted from theXY stage to increase the pressure within the chamber C, since a spacewithin the divider 2024 has been isolated by the divider 2016 andexhausted with a vacuum pipe 2010, there could be generated a pressuredeference between the pressure in the chamber C and that in the spacewithin the divider 2024, thus to control the pressure rise in the spacewithin the divider 2024 to be low. Preferably, the gap between thedivider 2016 and the sample surface should be approximately some ten μmto some mm, depending on the pressure level to be maintained within thechamber C and in the surrounding of the irradiating section 2002. It isto be understood that the interior of the divider 2016 is made tocommunicate with the vacuum pipe by the known method.

[0422] On the other hand, the charged beam irradiation apparatus maysometimes apply a high voltage of about some kV to the sample S, and soit is feared that any conductive materials located adjacent to thesample could cause an electric discharge. In this case, the divider 2016made of insulating material such as ceramic may be used in order toprevent any discharge between the sample S and the divider 2016.

[0423] It is to be noted that a ring member 2004-1 arranged so as tosurround the sample S (a wafer) is a plate-like adjusting part fixedlymounted on the sample table 2004 and set to have the same height withthe wafer so that a micro gap 2052 may be formed throughout a fullcircle of the tip portion of the divider 2016 even in a case of thecharged particles beam being irradiated against an edge portion of thesample such as the wafer. Thereby, whichever location on the sample Smay be irradiated by the charged beam, the constant micro gap 2052 canbe always formed in the tip portion of the divider 2016 so as tomaintain the pressure stable in the space 2024 surrounding the lenscolumn tip portion.

[0424]FIG. 22 shows a charged beam apparatus 2200 of a sixth embodimentof the present invention. A divider 2019 having a differential pumpingstructure integrated therein is arranged so as to surround the chargedparticles beam irradiating section 2002 of a lens column 2001. Thedivider 2019 is cylindrical in shape and has a circular channel 2020formed inside thereof and an exhausting path 2021 extending upwardlyfrom said circular channel 2020. Said exhausting path 2021 is connectedto a vacuum pipe 2023 via an inner space 2022. A micro space as narrowas a few some tens μm to a few some mm is formed between the lower endof the divider 2019 and the upper face of the sample S.

[0425] With such configuration, even if the gas is emitted from thestage in association with the movement of the stage resulting in anincrease of the pressure within the chamber C, and eventually is topossibly flow into the space of tip portion or the charged beamirradiating section 2002, the gas is blocked to flow in by the divider2019, which has reduced the gap between the sample S and itself so as tomake the conductance very low, thus to reduce the flow-in rate. Further,since any gas that has flown into is allowed to be evacuated through thecircular channel 2020 to the vacuum pipe 2023, there will be almost nogas remained to flow into the space 2024 surrounding the chargedparticles beam irradiating section 2002, and accordingly the pressure ofthe space surrounding the charged particles beam irradiating section2002 can be maintained to be a desired high vacuum level.

[0426]FIG. 23 shows a charged particles beam apparatus 2300 of a seventhembodiment of the present invention. A divider 2026 is arranged so as tosurround the charged beam irradiating section 2002 in the chamber C andaccordingly to isolate the charged beam irradiating section 2002 fromthe chamber C. This divider 2026 is coupled to a refrigeration system2030 via a support member 2029 made of material of high thermalconductivity such as copper or aluminum, and is kept as cool as −100° C.to −200° C. A member 2027 is provided for isolating a thermal conductionbetween the cooled divider 2026 and the lens column and is made ofmaterial of low thermal conductivity such as ceramic, resin or the like.Further, a member 2028 is made of insulating material such as ceramic orthe like and is attached to the lower end of the divider 2026 so as toprevent any electric discharge between the sample S and the divider2026.

[0427] With such configuration, any gas molecules attempting to flowinto the space surrounding the charged particles beam irradiatingsection from the chamber C are blocked by the divider 2026, and even ifthere are any molecules successfully flown into the section, they arefrozen to be captured on the surface of the divider 2026, thus allowingthe pressure in the space 2024 surrounding the charged beam irradiatingsection to be kept low. It is to be noted that a variety type ofrefrigeration system may be used for the refrigerating machine in thisembodiment, for example, a cooling machine using liquid nitrogen, a Herefrigerating machine, a pulse-tube type refrigerating machine or thelike.

[0428]FIG. 24 shows a charged particles beam apparatus 2400 of an eighthembodiment of the present invention. The division plates 2012 and 2014are arranged on both of the movable units of the stage 2003 similarly tothose illustrated in FIG. 20, and thereby, if the sample table 2004 ismoved to any locations, the space 2013 within the stage is separatedfrom the inner space of the chamber C by those division platescommunicating therewith through the narrow gaps 2050 and 2051.

[0429] Further, another divider 2016 similar to that as illustrated inFIG. 21 is formed surrounding the charged beam irradiating section 2002so as to separate a space 2024 accommodating the charged beamirradiating section 2002 therein from the interior of the chamber C witha narrow gap 2052 disposed therebetween. Owing to this, upon movement ofthe stage, even if the gas absorbed on the stage is desorbed into thespace 2013 to increase the pressure in this space, the pressure increasein the chamber C is kept to be low, and the pressure increase in thespace 2024 is also kept to be much lower. This allows the pressure inthe space 2024 for irradiating the charged beam to be maintained at lowpressure level.

[0430] Alternatively, employing the divider 2019 having the differentialpumping mechanism integrated therein as explained with reference to thedivider 2016, or the divider 2026 cooled with the refrigerating systemas shown in FIG. 22 allows the space 2024 to be maintained stably withfurther lowered pressure.

[0431]FIG. 25 schematically shows an exemplary optical system anddetection system of the charged beam apparatus 2500 of a ninthembodiment according to the present invention. The optical system isarranged within the lens column, and said optical system and a detectorare illustrative only, but the other optical systems and detectors maybe used when required. The optical system 2060 of the charged particlesbeam apparatus comprises a primary optical system 2061 for irradiating acharged particles beam against the sample S loaded on the stage 2003,and a secondary optical system 2071 to which secondary electronsemanated from the sample are introduced.

[0432] The primary optical system 2061 comprises; an electron gun 2062for emitting the charged beam; lens systems 2063 and 2064 composed oftwo stages of electrostatic lenses for converging the charged beamemitted from the electron gun 2011; a deflector 2065; a Wien filter oran E×B separator 2066 for deflecting the charged beam so as for anoptical axis thereof to be directed to perpendicular to the objectiveface; and lens systems 2067 and 2068 composed of two stages ofelectrostatic lenses, wherein said components of the primary opticalsystem 2061 are disposed in order from the electron gun 2062 placed inthe top so that the optical axis of the charged beam is inclined to theline orthogonal to the surface of the sample S (the sample plane), asshown in FIG. 25. The E×B deflecting system 2066 comprises an electrode2661 and a magnet 2662.

[0433] The secondary optical system 2071 is an optical system to whichthe secondary electrons emanated from the sample S are introduced, andcomprises lens systems 2072 and 2073 composed of two stages ofelectrostatic lenses arranged in an upper side of the E×B deflectingsystem 2066 of the primary optical system. The detector 2080 detects thesecondary electrons sent through the secondary optical system 2071.Since respective components and structures of the above optical systems2060 and the detector 2080 are the same as those according to the priorart, the detailed descriptions thereof should be omitted.

[0434] The charged particles beam emitted from the electron gun 2062 isformed with a square aperture of the electron gun and contracted withthe two-stage lens systems 2063 and 2064, and after the optical axisthereof having been adjusted by the deflector 2065, the beam is formedinto a square with respective edges of 1.25 mm on the deflecting centerplane of the E×B deflecting system 2066. The E×B deflecting system 2066is designed so that an electric field and a magnetic field are crossedwithin a plane orthogonal to a normal line of the sample, wherein whenthe relation among the electric field, the magnetic field and the energyof electrons satisfies a certain condition, the electrons are advancedstraight forward, and for the case other than the above, the electronsare deflected into a predetermined direction depending on said mutualrelation among the electric field, the magnetic field and the energy ofelectrons.

[0435] In FIG. 25, the charged particles beam from the electron gun isdirected to enter onto the sample S at a right angle, and further thesecondary electrons emanated from the sample is advanced straight towardthe detector 2080. The formed beam deflected by the E×B deflectingsystem is contracted to ⅕ in size with the lens systems 2067 and 2068 tobe projected onto the sample S. The secondary electrons emanated fromthe sample S with the data for a pattern image contained therein ismagnified with the lens systems 2067, 2068 and 2072, 2073, so as to forma secondary electron image on the detector 2080. These four stages ofmagnifying lenses, which are composed of the lens systems 2067 and 2068forming a symmetrical tablet lens and the lens systems 2072 and 2073forming another symmetrical tablet lens, make up the lenses of no.distortion.

[0436] When the defect inspection apparatus and method or the exposingapparatus and method according to either of the third to the eighthembodiments of the present invention is applied to the inspectionprocess (G) or the exposing process (c) in the flow chart illustratingan exemplary method for manufacturing a semiconductor device of FIGS. 12and 13, any fine patterns are allowed to be inspected or exposed stablywith higher accuracy, so that the yield of the products can be improvedand any faulty products can be prevented from being delivered. Accordingto the third to the ninth embodiments of the present invention, thefollowing effects may be expected to obtain.

[0437] (a) According to the fourth and the fifth embodiments (FIGS. 20A,20B and 21), the stage device can bring out a good performance ofaccurate positioning within vacuum atmosphere, and further the pressurein the space. surrounding the charged particles beam irradiatinglocation is hardly increased. That is, it allows the charged particlesbeam processing to be applied to the sample with high accuracy.

[0438] (b) According to the sixth embodiment (FIG. 22), it is almostimpossible for the gas emitted or leaked from the hydrostatic bearingsupport section to go though the divider and reach to the space for thecharged beam irradiating system. Thereby, the vacuum level in the spacesurrounding the charged beam irradiating location can be furtherstabilized.

[0439] (c) According to the seventh embodiment (FIG. 23), it is harderfor the desorbed gas to go through to the space for the chargedparticles beam irradiating system, and it is facilitated to maintain thevacuum level in the space surrounding the charged beam irradiatinglocation stable.

[0440] (d) According to the eighth embodiment (FIG. 24), the interior ofthe vacuum chamber is partitioned into three chambers, i.e., a chargedparticles beam irradiation chamber, a hydrostatic bearing chamber and anintermediate chamber which communicate with each other via a smallconductance. Further, the vacuum pumping system is constructed tocontrol the pressures in the respective chambers sequentially, such thatthe pressure in the charged particles beam irradiation chamber is thelowest, the intermediate chamber medium, and the hydrostatic bearingchamber the highest. The pressure fluctuation in the intermediatechamber can be reduced by the divider, and the pressure fluctuation inthe charged beam irradiation chamber can be further reduced by anotherstep of divider, so that the pressure fluctuation therein can be reducedsubstantially to a non-problematic level.

[0441] (e) According to the fifth to seventh embodiments of the presentinvention, the pressure increase upon movement of the stage can becontrolled to be low.

[0442] (f) According to the eighth embodiment (FIG. 24) of the presentinvention, the pressure increase upon movement of the stage can befurther controlled to be lower.

[0443] (g) According to the fifth to eighth embodiments of the presentinvention, since the defect inspection apparatus with highly accuratestage positioning performance and with a stable vacuum level in thecharged beam irradiating region can be accomplished, the inspectionapparatus with high inspection performance and without any fear ofcontamination of the sample can be provided.

[0444] (h) According to the fifth to eighth embodiments of the presentinvention, since the defect inspection apparatus with highly accuratestage positioning performance and with a stable vacuum level in thecharged particles beam irradiating region can be accomplished, theexposing apparatus with high exposing accuracy and without any fear ofcontamination of the sample can be provided.

[0445] (i) According to the fifth to eighth embodiments of the presentinvention, manufacturing the semiconductor by using the apparatus withhighly accurate stage positioning performance and with a stable vacuumlevel in the charged beam irradiating region allows to form a finesemiconductor circuit.

[0446] A tenth and an eleventh embodiments of the present invention willnow be described below with reference to FIGS. 26 to 33. FIG. 26 shows aschematic configuration of a defect inspection apparatus 3000 accordingto the tenth embodiment of the present invention.

[0447] This defect inspection apparatus is, what is called, an imageprojection type inspection apparatus, which comprises: an electron gun3001 for emitting a primary electron beam; an electrostatic lens 3002for forming the emitted primary electron beam; an E×B deflecting system3003 for deflecting the accordingly formed primary electron beam at afield where an electric field “E” and a magnetic field “B” are crossedat a right angle, so that the beam impinges against a semiconductorwafer 3005 at an approximately right angle; an objective lens 3010 forforming the deflected primary electron beam into an image on the wafer3005; a stage 3004 arranged in a sample chamber(not shown) allowed to beevacuated to vacuum and capable of moving within a horizontal plane withthe wafer 3005 loaded thereon; an electrostatic lens 3006 in a mapprojection system for map-projecting at a predetermined magnification asecondary electron beam and/or a reflected electron beam emanated fromthe wafer 3005 upon the irradiation of the primary electron beam to beformed into an image; a detector 3007 for detecting the formed image asa secondary electron image of the wafer; and a control section 3016 forcontrolling the whole unit of the apparatus and for performing theprocess for detecting a defect in the wafer 3005 based on the secondaryelectron image detected by the detector 3007, as well.

[0448] It is to be noted that the present specification has designatedsaid image as the secondary electron image, although said secondaryelectron image actually affected by not only the secondary electrons butalso the contribution of the scattered electrons and the reflectedelectrons.

[0449] Further, between the objective lens 3010 and the wafer 3005,there is arranged a deflecting electrode 3011 for deflecting an incidentangle of the primary electron beam onto the wafer 3005 by the electricfield or the like. This deflecting electrode 3011 is connected with adeflection controller 3012 for controlling the electric field of saiddeflecting electrode. This deflection controller 3012 is connected tothe control section 3016 to control the deflecting electrode 3011 sothat the electric field may be generated by said deflecting electrode3011 in response to a command from the control section 3016. It is to benoted that the deflection controller 3012 may be a voltage controllerfor controlling a voltage applied to the deflecting electrode 3011.

[0450] The detector 3007 may have any arbitrary configuration so far asit can convert the secondary electron image formed by the electrostaticlens 3006 into a signal capable of being processed later. For example,as shown in detail in FIG. 31, the detector 3007 may comprise amulti-channel plate 3050, a fluorescent screen 3052, a relay opticalsystem 3054, and an image sensor 3056 composed of a plurality of CCDelements. The multi-channel plate 3050 comprises a plurality of channelswithin the plate so as to generate more electrons during the secondaryelectrons formed into the image by the electrostatic lens 3006 passingthrough those channels. That is, the multi-channel plate 3050 amplifiesthe secondary electrons.

[0451] The fluorescent screen 3052 emits fluorescence by the amplifiedsecondary electrons to convert the secondary electrons into light(fluorescence). The relay lens 3054 guides said fluorescence to the CCDimage sensor 3056, and then said CCD image sensor 3056 converts theintensity distribution of the secondary electrons on the surface of thewafer 3005 to an electric signal, i.e., a digital image data for eachelement, which in turn is output to the control section 3016.

[0452] The control section 3016, as shown in FIG. 26, may be composed ofa general-purpose computer or the like. This computer may comprise acontrol section main unit 3014 for executing various controls andoperations according to a predetermined program, a CRT 3015 fordisplaying processed results from the main unit 3014, and an inputsection 3018 such as a mouse or a keyboard used by an operator forinputting an command, and, of course, said control section 3016 may becomposed of a hardware working exclusively for a defect inspectionapparatus, a work station, or the like.

[0453] The control section main unit 3014 may comprises various controlsubstrates such as a CPU, a RAM, a ROM, a hard disk, and a videosubstrate, which are not illustrated. A secondary electron image storageregion 3008 is allocated onto the memory such as the RAM or the harddisk, for storing the electric signal received from the detector 3007,i.e., the digital image data for the secondary electron image of thewafer 3005. Further, on the hard disk, there is a reference imagestorage section 3013 for storing beforehand a reference image data ofthe wafer having no defect. Still further, on the hard disk, in additionto the control program for controlling the whole unit of the defectinspection apparatus, a defect detection program 3009 is stored forreading the secondary electron image data from the storage region 3008and automatically detecting a defect in the wafer 3005 based on saidimage data according to the predetermined algorithm.

[0454] This defect detection program 3009, as will be described in moredetail later, has such a function that it performs a matching ofreference image read out from the reference image storage section 3013to an actually detected secondary electron image in order toautomatically detect any defective parts, so that it may indicate awarning to the operator when it determines there is the defect existing.In this regard, the CRT 3015 may be designed to also display thesecondary electron image 3017 on the display section thereof.

[0455] Then, an operation in the defect inspection apparatus 3000according to the tenth embodiment will be described referring to thoseflow charts of FIGS. 28 to 30.

[0456] First of all, as shown in the flow of the main routine of FIG.28, the wafer 3005 to be inspected is placed on the stage 3004 (step3300). In this regard, the way of setting the wafer 3005 may take such aform that each of a plurality of wafers 3005 contained in a loader,though not shown, is set on the stage 3004 automatically one by one.

[0457] Then, images for a plurality of regions to be inspected arerespectively obtained, which are displaces one from another while beingsuperimposed partially one on another on the XY plane of the surface ofthe wafer 3005 (Step 3304). Each of said plurality of regions to beinspected, from which the image is to be obtained, is a rectangularregion as designated by reference numeral 3032 a, 3032 b . . . 3032 k .. . each of which is observed to be displaced relative to one anotherwhile being partially superimposed one on another around the inspectionpattern 3030 of the wafer. For example, 16 pieces of images for theregions to be inspected 3032 (the images to be inspected) may beobtained as shown in FIG. 27. Herein, for the image as shown in FIG. 27,each square contained in the rectangle region corresponds to one pixel(or a block, whose unit is greater than the unit of pixel), and amongthose squares, shaded ones correspond to the imaged area of the patternon the wafer 3005. This step 3304 will be described in more detail laterwith reference to the flow chart of FIG. 29.

[0458] Then the process compares the image data for the plurality ofregions to be inspected, which have been obtained at Step 3304,respectively with the reference image stored in the storage section 3013to look for any matching (Step 3308 in FIG. 3), and determines whetheror not there is a defect existing in the wafer inspection planeencompassed by said plurality of regions to be inspected. This processperforms, what is called, the matching operation between image data,which will be explained later in detail with reference to the flow chartshown in FIG. 30.

[0459] If the result from the comparing process at Step 3308 indicatesthat there is a defect in the wafer inspection plane encompassed by saidplurality of regions to be inspected (Step 3312, affirmativedetermination), the process gives a warning to the operator indicatingthe existence of the defect (Step 3318). As for the way of warning, forexample, the display section of the CRT 3015 may display a messagenoticing the operator that there is a defect, or at the same time mayadditionally display a magnified image 3017 of the pattern determined tohave the defect. Such defective wafers may be immediately taken out of asample chamber 3 and stored in another storage separately from thosewafers having no defect (Step 3319).

[0460] If the result from the comparing process at Step 3308 indicatesthat there is no defect in the wafer 3005 (Step 3312, negativedetermination), the process determines whether or not there are remainedmore regions to be inspected for the wafer 3005 currently treated as theinspection object (Step 3314). If there are more regions remained forinspection (Step 3314, affirmative determination), the stage 3004 isdriven to move the wafer 3005 so that other regions to be furtherinspected are positioned within the irradiative region of the primaryelectron beam (Step 3316). Subsequently, the process goes back to Step3302 to repeat the similar operations for said other regions to beinspected.

[0461] If there is no more regions remained to be further inspected(Step 3314, negative determination), or after a drawing out processingof the defective wafer (Step 3319), the process determines whether ornot the current wafer treated as the inspection object is the last waferto be inspected, that is, whether or not there are any wafers remainingfor the inspection in the loader, though not shown (Step 3320). If thecurrent wafer is not the last one (Step 3320, negative determination),the wafers having been inspected already are stored in a predeterminedstoring location, and a new wafer which has not been inspected yet isset instead on the stage 3004 (Step 3322). Then, the process goes backto Step 3302 to repeat the similar operations for said wafer. Incontrast, the current wafer is the last one (Step 3320, affirmativedetermination), the wafer having been inspected is stored in thepredetermined storing location to end the whole process.

[0462] Then, the process flow of step 3304 will now be described withreference to the flow chart of FIG. 29. In FIG. 29, first of all, animage number “i” is set to the initial value “1” (Step 3330). This imagenumber is an identification number assigned serially to each of theplurality of images for the regions to be inspected. Secondary, theprocess determines an image position (Xi,Yi) for the region to beinspected as designated by the set image number i (Step 3332).

[0463] This image position is defined as a specific location within theregion to be inspected for bounding said region, for example, a centrallocation within said region. Currently, i=1 defines the image positionas (X1, Y1), which corresponds, for example, to a central location ofthe region to be inspected 3032 a as shown in FIG. 32. The imageposition has been determined previously for every image region to beinspected, and stored, for example, in the hard disk of the controlsection 3016 to be read out at Step 3332.

[0464] Then, the deflection controller 3012 applies a potential to thedeflecting electrode 3011 (Step 3334 in FIG. 29) so that the primaryelectron beam passing through the deflecting electrode 3011 of FIG. 26may be irradiated against the image region to be inspected in the imageposition (Xi, Yi) determined at Step 3332.

[0465] Then, the electron gun 3001 emits the primary electron beam,which goes through the electrostatic lens 3002, the E×B deflectingsystem 3003, the objective lens 3010 and the deflecting electrode 3011,and eventually impinges upon a surface of the set wafer 3005 (Step3336). At that time, the primary electron beam is deflected by anelectric field generated by the deflecting electrode 3011 so as to beirradiated onto the wafer inspection surface 3034 covering the wholeimage region to be inspected at the image position (Xi, Yi). When i=1,the region to be inspected is 3032 a.

[0466] The secondary electrons and/or the reflected electrons (hereafterreferred exclusively to as “secondary electrons” for simplification) areemanated from the region to be inspected, to which the primary electronbeam has been irradiated. Then, the generated secondary electron beam isformed into an image on the detector 3007 at a predeterminedmagnification by the electrostatic lens 3006 of a magnifying projectionsystem. The detector 3007 detects the imaged secondary electron beam,and converts it into an electric signal for each detecting element,i.e., a digital image data (Step 3338). Then, the detected digital imagedata for the image number i is sent to the secondary electron imagestorage region 3008 (Step 3340).

[0467] Subsequently, the image number i is incremented by 1 (Step 3342),and the process determines whether or not the incremented image number(i+1) is greater than a constant value “iMAX” (Step 3344). This iMAX isthe number of images to be inspected that are required to obtain, whichis “16” for the above example of FIG. 27.

[0468] If the image number i is not greater than the constant value iMAX(Step 3344, negative determination), the process goes back to Step 3332again, and determines again the image position (Xi+1, Yi+1) for theincremented image number (i+1). This image position is a position movedfrom the image position (Xi, Yi) determined at the previous routine by aspecified distance (AXi, AYi) in the X direction and/or Y direction. Theregion to be inspected in the example of FIG. 32 is at the location (X2,Y2), i.e., the rectangular region 3032 b indicated with the dotted line,which has been moved from the position (X1, Y1) only in the Y direction.It is to be noted that the value for (ΔXi, ΔYi) (i=1,2 . . . iMAX) mayhave been appropriately determined from the data indicating practicallyand experimentally how much is the displacement of the pattern 3030 onthe wafer inspection surface 3034 from the field of view of the detector3007 and a number and an area of the regions to be inspected.

[0469] Then, the operations for Step 3332 to Step 3342 are repeated inorder for iMAX regions to be inspected. These regions to be inspectedare continuously displaced while being partially superimposed one onanother on the wafer inspection surface 3034 so that the image positionafter k times of movement (Xk,Yk) corresponds to the inspection imageregion 3032 k, as shown in FIG. 32. In this way, the 16 pieces ofinspection image data exemplarily illustrated in FIG. 27 are obtained inthe image storage region 3008. It is observed that a plurality of imagesobtained for the regions to be inspected 3032(i.e., inspection image)contains partially or fully the image 3030 a of the pattern 3030 on thewafer inspection surface 3034, as illustrated in FIG. 27.

[0470] If the incremented image number i has become greater than iMAX(Step 3344, affirmative determination), the process returns out of thissubroutine and goes to the comparing process (Step 3308) of the mainroutine of FIG. 28.

[0471] It is to be noted that the image data that has been transferredto the memory at Step 3340 is composed of intensity values of thesecondary electrons for each pixel (so-called, raw data), and these datamay be stored in the storage region 3008 after having been processedthrough various operations in order to use for performing the matchingoperation relative to the reference image in the subsequent comparingprocess (Step 3308 of FIG. 28).

[0472] Such operations includes, for example, a normalizing process forsetting a size and/or a density of the image data to be matched with thesize and/or the density of the reference image data, or the process foreliminating as a noise the isolated group of elements having the pixelsnot greater than the specified number. Further, the image data may beconverted by means of data compression into a feature matrix havingextracted features of the detected pattern rather than the simple rawdata, so far as it does not negatively affect to the accuracy indetection of the highly precise pattern.

[0473] Such feature matrix includes, for example, m×n feature matrix, inwhich a two-dimensional inspection region composed of M×N pixels isdivided into m×n (m<M, n<N) blocks, and respective sums of intensityvalues of the secondary electrons of the pixels contained in each block(or the normalized value defined by dividing said respective sums by atotal number of pixels covering all of the regions to be inspected)should be employed as respective components of the matrix. In this case,the reference image data also should have been stored in the same formof representation. The image data in the content used in the tenthembodiment of the present invention includes, of course, a simple rawdata but also includes any image data having the feature extracted byany arbitrary algorithms as described above.

[0474] The process flow for Step 3308 will now be described withreference to the flow chart of FIG. 30. First of all, the CPU in thecontrol section 3016 (FIG. 26) reads the reference image data out of thereference image storage section 3013 (FIG. 26) onto the working memorysuch as the RAM or the like (Step 3350). This reference image isidentified by reference numeral 3036 in FIG. 27. Then, the image number“i” is reset to 1 (Step 3352), and then the process reads out theinspection image data having the image number i onto the working memory(Step 3354).

[0475] Then, the read out reference image data is compared with the dataof the image i for any matching to calculate a distance value “Di”between both data (Step 3356). This distance value Di indicates asimilarity level between the reference image and the image to beinspected “i”, wherein a greater distance value indicates the greaterdifference between the reference image and the inspection image. Anyunit of amount representative of the similarity level may be used forsaid distance value Di.

[0476] For example, if the image data is composed of M×N pixels, theprocess may consider that the secondary electron intensity (or theamount representative of the feature) for each pixel is each of theposition vector components of M×N dimensional space, and then calculatean Euclidean distance or a correlation coefficient between the referenceimage vector and the image i vector in the M×N dimensional space. Itwill be easily appreciated that any distance other than the Euclideandistance, for example, the urban area distance may be calculated.Further, if the number of pixels is huge, which increases the amount ofthe operation significantly, then the process may calculates thedistance value between both image data represented by the m×n featurevector as described above.

[0477] Subsequently, it is determined if the calculated distance valueDi is smaller than a predetermined threshold Th (Step 3358). Thisthreshold Th is determined experimentally as a criteria for judging asufficient matching between the reference image and the inspection imageto be inspected.

[0478] If the distance value Di is smaller than the predeterminedthreshold Th (Step 3358, affirmative determination), the processdetermines that the inspection plane 3034 of said wafer 3005 has “nodefect” (Step 3360) and returns out of this sub routine. That is, ifthere is found at least one image among those inspection images matchingto the reference image, the process determines there is “no defect”.Accordingly, since the matching operation shall not necessarily beapplied to every inspection image, the high-speed judgment becomespossible. As for the example of FIG. 27, it is observed that the imageto be inspected at the column 3 of the row 3 is approximately matchingto the reference image without any offset thereto.

[0479] When the distance value Di is not smaller than the threshold Th(Step 3358, negative determination), the image number i is incrementedby 1 (Step 3362), and then it is determined whether or not theincremented image number (i+1) is greater than the predetermined valueiMAX (Step 3364).

[0480] If the image number i is not greater than the predetermined valueiMAX (Step 3364 negative determination), the process goes back to Step3354 again, reads out the image data for the incremented image number(i+1), and repeats the similar operations.

[0481] If the image number i is greater than the predetermined valueIMAX (Step 3364, affirmative determination), then the process determinesthat said inspection plane 3034 of said wafer 3005 has “a defectexisting” (Step 3366), and returns out of the sub routine. That is, ifany one of the images to be inspected is not approximately matching tothe reference image, the process determined that there is “a defectexisting”. A defect inspection apparatus 3000 according to the presentinvention may use not only the electron beam apparatus of the imageprojective type as described above but also an electron beam apparatusof, what is called, the scanning type. This will now be explained as aneleventh embodiment with reference to FIG. 33.

[0482]FIG. 33 is a schematic diagram of an electron beam apparatus ofthe eleventh embodiment according to the present invention, in which theelectron beam emitted from an electron gun 3061 is converged by acondenser lens 3062 to form a crossover at a point 3064.

[0483] Beneath the condenser lens 3062 a first multi-aperture plate 3063having a plurality of apertures is disposed, thereby to form a pluralityof primary electron beams. Each of those primary electron beams formedby the first multi-aperture plate 3063 is contracted by a demagnifyinglens 3065 to be projected onto a point 3075. After being focused on thepoint 3075, the first electron beams are further focused onto a sample3068 by an objective lens 3067. A plurality of first electron beamsexited from the first multi-aperture plate 3063 is deflected alltogether by a deflecting system 3080 arranged between the demagnifyinglens 3065 and the objective lens 3067 so as to scan the surface of thesample 3068.

[0484] In order not to produce any field curvature aberration by thedemagnifying lens 3065 and the objective lens 3067, as shown in FIG. 33,the multi-aperture plate is provided with a plurality of small apertureslocated along a circle such that projections thereof in the X directionis equally spaced.

[0485] A plurality of focused primary electron beams is irradiated ontothe sample 3068 at a plurality of points thereon, and secondaryelectrons emanated from said plurality of points are attracted by anelectric field of the objective lens 3067 to be converged narrower, andthen deflected by an E×B separator 3066 so as to be introduced into asecondary optical system. The secondary electron image is focused on thepoint 3076 which is much closer to the objective lens 3067 than thepoint 3075. This is because each of the primary electron beams has theenergy of 500 eV on the surface of the sample, while the secondaryelectron beam only has the energy of a few eV.

[0486] The secondary optical system has a magnifying lens 3069 and 3070,wherein the secondary electron beam after passing through thosemagnifying lenses 3069 and 3070 is imaged on a plurality of apertures ina second multi-aperture plate 3071. Then, the second electron beampasses through those apertures to be detected by a plurality ofdetectors 3072. It is to be noted that the plurality of apertures formedthrough the second multi-aperture plate 3071 disposed in front of thedetectors 3072 corresponds to the plurality of apertures formed throughthe first multi-aperture plate 3063 on one to one basis.

[0487] Each of the detectors 3072 converts the detected secondaryelectron beam into an electric signal representative of its intensity.Such electric signals output from respective detectors, after beingamplified respectively by an amplifier 3073, are received by an imageprocessing section 3074 so as to be converted into image data. Since theimage processing section 3074 is further supplied with a scanning signalfrom the deflecting system 3080 for deflecting the primary electronbeam, the image processing section 3074 can display an imagerepresenting the surface of the sample 3068. This image corresponds toone of those plural images to be inspected at the different locations(FIG. 27) as described with reference to the tenth embodiment.

[0488] Comparing this image with the reference image 3036 allows anydefects in the sample 3068 to be detected. Further, the line width ofthe pattern on the sample 3068 can be measured in such a way that theevaluation pattern on the sample 3068 is moved by a registration to theproximity of an optical axis of the primary optical system, and theevaluation pattern is then line-scanned to extract the line widthevaluation signal, which is in turn appropriately calibrated.

[0489] In this regard, it is preferred to make arrangements when theprimary electrons passed through the apertures of the firstmulti-aperture plate 3063 is focused onto the surface of the sample3068, and then the secondary electrons emanated from the sample 3068 areformed into an image on the detector 3072, in order to minimize theaffection by the three aberrations, i.e., the distortion caused by theprimary electron optical systems, the field curvature, and theastigmatism.

[0490] Then, regarding the relation between the spacing in the pluralityof primary electron beams and the secondary electron optical system, ifthe space between respective primary electron beams is determined to begreater than the aberration of the secondary optical system, then thecross talk among a plurality of beams can be eliminated.

[0491] Also in the scanning electron beam apparatus 3100 of FIG. 33, thesample 3068 is inspected according to the flow chart as illustrated inFIGS. 28 and 29. In this case, the image position (Xi, Yi) at Step 3332of FIG. 29 corresponds to the central location of the two-dimensionalimage made by combining a plurality of line images obtained throughscanning with the multi-beam. This image position (Xi, Yi) could besequentially modified in the subsequent processes, which may beperformed by, for example, changing the offset voltage of the deflectingsystem 3080. The deflecting system 3080 performs the normal linescanning by changing the voltage around the set offset voltage. It isapparent that a separate deflecting means other than the deflectingsystem 3080 may be employed to control the image position (Xi, Yi).

[0492] A defect inspection apparatus described in either of the tenth orthe eleventh embodiment may be applied to the semiconductor devicemanufacturing processes of FIGS. 12 and 13 for a wafer evaluation. Thoseflow charts of FIGS. 12 and 13 includes a wafer manufacturing processfor manufacturing the wafer (or a wafer preparing process for preparingthe wafer), a mask fabrication process for fabricating the mask to beused in the exposing process (or a mask preparing process for preparingthe mask), a wafer fabrication process for performing any necessaryprocesses for a wafer, a chip assembling process for cutting out chipsformed on the wafer one by one so as to be operative, and a chipinspection process for inspecting those assembled chips.

[0493] Among these processes, the main process that decisively affectsthe performance of the device is the wafer processing process. In thiswafer processing process, the designed circuit patterns are printed onthe wafer one on another, thus to form many chips which will work asmemories or CPUs. This wafer processing process includes the followingrespective processes:

[0494] (1) A thin film deposition process for forming a dielectric thinfilm to be used as an insulation layer and/or a metallic thin film toform an interconnect section or an electrode section, or the likes (byusing the CVD process or the sputtering);

[0495] (2) An oxidation process for oxidizing the deposited thin filmlayer and/or the wafer substrate;

[0496] (3) A lithography process for forming a pattern of the resist byusing the mask (reticle) in order to selectively process the thin filmlayer and/or the wafer substrate;

[0497] (4) An etching process for processing the thin film layer and/orthe wafer substrate in accordance with the resist pattern (e.g., byusing the dry etching process);

[0498] (5) An ions/impurities implantation and diffusion process;

[0499] (6) A resist stripping process; and

[0500] (7) An inspection process for inspecting the processed wafer.

[0501] It should be noted that, the wafer processing process must beperformed repeatedly depending on the number of layers required thus tomanufacture the semiconductor device that will be operative as designed.

[0502] The flow chart of FIG. 13 shows the lithography process which isa core process in the wafer processing processes described above. Thelithography process comprises the respective processes as describedbelow:

[0503] (1) A resist coating process for coating the wafer having thecircuit pattern formed thereon in the previous process, with the resist;

[0504] (2) An exposing process for exposing the resist;

[0505] (3) A developing process for developing the exposed resist toobtain the pattern of the resist; and

[0506] (4) An annealing process for stabilizing the developed pattern.

[0507] Any known processes may be applied to the semiconductor devicemanufacturing process, the wafer processing process and the lithographyprocess described above.

[0508] When the defect inspection apparatus according to either of theabove described embodiments of the present invention is used in theabove (7) wafer inspection process, the apparatus can inspect even asemiconductor device having a fine pattern for defect detection withhigh accuracy under the conditions where there is no resultant faultyimage for the secondary electron image, so that a yield of the productscan be improved and any defective products can be prevented from beingdelivered into the market.

[0509] The present invention is not limited only to the aboveembodiments but also may be modified arbitrarily and preferably withoutdeparting from the scope and spirit of the present invention. Forexample, although the description has illustratively employed asemiconductor wafer 3005 as a sample to be inspected, the sample to beinspected in the present invention is not limited to this but anythingmay be selected as the sample so far as it can be inspected for defectsby using the electron beam. For example, the object to be inspected maybe a mask with an exposure pattern formed thereon.

[0510] Further, the present invention may be applied not only to anapparatus which detects any defects with charged particle beams otherthan electrons but also to any apparatus which allows any images to beobtained for inspecting the sample for defect detection.

[0511] Still further, the deflecting electrode 3011 may be disposed notonly between the objective lens 3010 and the wafer 3005 but also at anyarbitrary locations so far as the irradiation region of the primaryelectron beam can be controlled. For example, the deflecting electrode3011 may be disposed between the E×B deflecting system 3003 and theobjective lens 3010, or between the electron gun 3001 and the E×Bdeflecting system 3003. Further the E×B deflecting system 3003 maycontrol the deflecting direction by controlling the field generatedthereby. That is, the E×B deflecting system 3003 may function also asthe deflecting electrode 3011.

[0512] Further, although in the above tenth and eleventh embodiments,either one of the matching between the pixels and the matching betweenthe feature vectors has been employed for the matching operation betweenimage data, they may be combined together for it. For example, a muchfaster and more precise matching process can be constructed by two-stepmatching, in which firstly a high-speed matching is performed with thefeature vectors which requires fewer number of operations, andsubsequently the more precise matching is performed with more detailedpixel data for the images to be inspected that have been found to bequite similar.

[0513] Still further, although in the tenth and the eleventh embodimentsaccording to the present invention, the position mismatch for the imageto be inspected has been resolved only by displacing the irradiatingregion of the primary electron beam, the present invention may becombined with a process for retrieving an optimal matching region on theimage data before or during the matching processes (e.g., firstdetecting the regions having higher correlation coefficient and thenperforming the matching). This can improve the accuracy in defectdetection, because the major position mismatch for the image to beinspected is rectified by displacing the irradiating region of theprimary electron beam, while the relatively minor position mismatch canbe absorbed subsequently with the digital image processing.

[0514] Yet further, although the configurations for an electron beamapparatus for defect detection have been illustratively shown in FIGS.26 and 33, the electron optical systems or the like may be preferablyand arbitrarily modified so far as it functions well. For example,although each of the electron beam irradiation means (3001, 3002, 3003)shown in FIG. 26 has been designed so as to irradiate the primaryelectron beam onto the surface of the wafer 3005 at a right angle fromabove, the E×B deflecting system 3003 may be omitted so that the primaryelectron beam may diagonally impinge upon the wafer 3005.

[0515] Still further, the flow in the flow chart of FIG. 28 is also notlimited to the illustrated one. For example, although in the embodimentthe process does not further perform the defect detection in any otherregions of the sample that has been determined to have a defect at Step3312, the flow may be modified so that the overall area can be inspectedfor any defects to be detected. Yet further, if the irradiating area ofthe primary electron beam can be expanded so as to cover almost overallarea of the sample with one shot of irradiation, Steps 3314 and 3316 canbe omitted.

[0516] As described above in detail, according to the defect inspectionapparatus of the tenth and the eleventh embodiment of the presentinvention, since the defect in the sample can be detected by firstobtaining respective images of a plurality of regions to be inspected,which are displaced from one another while being partially superimposedone on another on the sample, and comparing those images of the regionsto be inspected with the reference image, therefore an advantageouseffect can be provided in that the accuracy in the defect detection canbe prevented from being deteriorated.

[0517] Further, according to the device manufacturing method employingthe tenth and the eleventh embodiments of the present invention, sincethe defect detection is performed by using such a defect inspectionapparatus as described above, therefore another advantageous effect canbe provided in that the yield of the products can be improved and anyfaulty products can be prevented from being delivered.

[0518]FIG. 34 shows an electron beam apparatus 4000 of a twelfthembodiment according to the present invention.

[0519] As can be seen from FIG. 34, this electron beam apparatuscomprises an electron gun 4001 for irradiating a primary electron beamagainst a sample T, and a secondary electron detector 4011 for detectingsecondary electron beam from the sample T.

[0520] The electron beam emitted from an electron gun 4001 is convergedby a condenser lens 4002 to form a crossover on an aperture 4004 whichdetermines NA (numerical aperture). Beneath the condenser lens 4002 isdisposed a multi-aperture plate 4003 which is provided with 8 apertures4014 in total as shown in FIG. 35. Said apertures 4014 are imaged on adeflection principal plane of an E×B deflecting system 4006 by ademagnifying lens 4005, and further contracted by an objective lens 4007and projected onto the sample T to form resultantly primary electronbeam irradiation points E (FIG. 36). Those second electrons emanatedfrom respective primary electron beam irradiation points E are deflectedby the E×B deflecting system 4006 to the right hand side on paper andmagnified by a secondary optical system 4009 so as to be imaged on agroup of apertures of detectors 4010. The sample T is carried on amovable stage (not shown) so as to be moved in the direction normal topaper of FIG. 34 (Y direction).

[0521] Although the array of apertures 4014 of the aperture plate 4003is designed as 3 rows×3 columns, as shown in FIG. 35, preferably theapertures 4014 should be formed within only such a specific diameterthat has the intensity of the electrons emitted from the electron gun(electron current density) greater than a certain level, and so in theillustrated example, the aperture on the third row at the third columnhas not been provided. Further, the apertures at the second and thethird rows are offset respectively with respect to the apertures at thefirst and the second rows toward the right direction viewed in FIG. 35by the amount of ⅓ of the distance D1 between the columns.

[0522] Still further, those distances D1 and D2 between the apertures4014 are designed so that the spacing between the irradiation points ofthe primary electron beams on the sample may be sufficient. Thisarrangement is employed to prevent any possible cross talks of thesecondary electron images among respective beams on the group ofapertures of the detector 4010 since the secondary optical system has alarger angular aperture to improve the detection efficiency andaccordingly has large degree of aberration which could cause the abovecross talks.

[0523]FIGS. 35B and 35C are plan views of aperture plates 4050 and 4060,each having apertures formed therein along a circle respectively.Projected points onto the x-axis of apertures 4051, 4052, . . . of theaperture plate 4050 shown in FIG. 35B are equally spaced by Lx, andsimilarly, projected points onto the x-axis of apertures 4061, 4062, . .. of the aperture plate 4060 shown in FIG. 35C are also equally spacedby Lx. In the electron beam apparatus 4000 according to an embodiment ofthe present invention, each of the primary electron beams is disposed soas to minimize a maximum value of distances between any adjacent primaryelectron beams to be arranged two-dimensionally on a sample surface.

[0524] Distance ratios between adjacent two apertures of the apertureplate 4050 shown in FIG. 35B, which are designated by 50 a, 50 b, 50 eand 50 f, are 47, 63, 63 and 41 respectively, and distance ratiosbetween adjacent two apertures of the aperture plate 4060 shown in FIG.35C, which are designated by 60 a, 60 b and 60 f, are 56, 57 and 41respectively. By comparison between these two aperture plates, it isfound that since in the aperture plates 4060, the maximum value of thedistance ratios between adjacent primary electron beams is 57, which issmaller than 50 b (63) of the aperture plate 4050, the aperture plate4060 of FIG. 35C is superior to the aperture plate 4050 of FIG. 35B inthe arrangement of the apertures.

[0525] Using the aperture plate with such a condition described above isadvantageous in that the distances between actually adjacent primarybeams are approximately equal, thus providing good symmetry property,that the astigmatism is not likely to occur, that since being spacedapart from each other, the primary electron beam is not likely to bemade blur by the space charge effect, and that since respective primaryelectron beams are irradiated onto the sample at or near to symmetricpositions thereon respectively, an effect of charging on the sample maybe alleviated.

[0526] The primary electron beam is separated into a plurality of beamsby those small apertures 4014, and they are imaged on the deflectionprincipal plane of the E×B deflecting system 4006 by the demanifyinglens 4005, further contracted by the objective lens 4007 and projectedonto the sample T to resultantly form the primary electron beamirradiation points E as shown in FIG. 36.

[0527] Those second electrons emanated from respective primary electronbeam irradiation points E are accelerated and converged in an electricfield applied between the objective lens 4007 and the sample surface,deflected by the E×B deflecting system 4006 disposed between theobjective lens 4007 and another lens on the electron gun side to theright hand side in FIG. 34, magnified by the lens 4009 of the secondaryoptical system to be imaged on the detective aperture plate 4010 havinga plurality of apertures formed therethrough, and finally detected bythe secondary electron detector 4011. The sample T is carried on amovable stage (not shown) so as to be moved in the direction normal topaper of FIG. 34 (Y direction).

[0528] Further, those distances D1 and D2 between the small apertures4014 are designed so that the spacing between the irradiation points ofthe primary electron beams on the sample T may be sufficient. For a casewhere the spacing between the irradiation points is not constant, thesmallest value for the spacing will be a matter of problem and saidsmallest value for the spacing is accordingly required to be made aslarge as possible. This is required to prevent any possible cross talksof the secondary electron images among respective secondary electronbeams on the detective aperture plate 4010 since the secondary opticalsystem has a larger angular aperture to improve the detection efficiencyand accordingly has large degree of aberration which could cause theabove cross talks.

[0529] The deflecting system 4012 and 4013 for electron beam scanninghave been designed so as to cause a scanning motion of the primaryelectron beam irradiation points E on the sample T in the directiontoward the column on the right hand side (X direction) viewed in FIG.35, and the scanning distance S should be designed so as to beequivalent to the amount of about ⅓ of the spacing H between the columnsof the irradiation points E (S=H/3+α).

[0530] Then, after the sample T being moved in the Y direction by thedistance encompassing the region to be detected, the stage is moved bystep in the X direction to move the sample in the X direction by 400 μm,and then as similarly to the above description, the raster scanning (inthe X direction by 400 μm+α) will be performed while continuously movingthe stage in the −Y direction. Repeating said processes may provide theimage data for every region to be inspected.

[0531] When the inspection of the sample T is carried out in saidelectron beam apparatus, the movable stage 4020 is moved so as to movethe sample in the Y direction continuously. During this movement, thescanning deflectors 4012 and 4014 causes the scanning motion of each ofthe primary electron beam irradiation points E in the X direction by⅓H+α as described above, and in an exemplary case where the spacing Hbetween the respective primary electron beam irradiation points E is 150μm, each of the primary electron beam irradiation points E accomplishesthe scanning with the width of (150 μm×⅓)+α to obtain the image data forthe range of (150 μm×⅓)×8 (points) (=400 μm+α) as a whole. When thesample is moved by the distance equivalent to the length of the samplein the Y direction, the movable stage moves the sample in the Xdirection by 400 μm and the scanning is carried out by the retracemovement in the Y direction as similarly to the above description.

[0532] Comparing this image data with the image obtainable from apredetermined pattern data accomplishes a desired inspection. Since inthe illustrated example, 8 channels have been employed to receive thesignals and also the serial inspection has been carried out during theperiod other than the time required for the retrace movement, theprocessing speed will be significantly improved to be higher incomparison with that in the prior art. It is to be noted that, when theinspection region width of the sample (the width in the X direction)being assumed to be 200 mm, the number of retraces is calculated as 200mm/0.4 mm=500 times, and this value is approximately equivalent to 4minutes to be necessary for the retrace scanning in the overallinspection of one piece of sample with the rate of 0.5 second for eachretrace, which seems to be extremely short. It is also noted that anaxis-symmetrical electrode is designated by the reference numeral 4020in FIG. 34.

[0533] In case of the measurement of the line width, preferably each ofthe scanning deflectors 4012 and 4013 is made in the form of an octupoleto also allow the scanning motion in the Y direction, in which the beamis moved to a location of the pattern to be measured by being deflectedin the X direction, and then the Y directional scanning motion may beperformed. In case of the measurement of the pattern line width in the Xdirection, the beam should be moved to a location of the pattern to bemeasured by adjusting the stage position and also by being deflected inthe Y direction, and then the X directionally scanning motion and thesignal processing similar to that in the prior art may be appliedthereto.

[0534] In case of an alignment accuracy measurement, the patternemployable for evaluating the alignment accuracy should have beenfabricated and then the scanning similar to that for the line widthmeasurement may be performed.

[0535] It is to be noted that in the 12th embodiment (FIG. 34), a singleelectron beam irradiating system with a single electron gun 4001 hasbeen shown for the illustrative purpose, a plurality of electron beamirradiating systems may be employed which comprises a plurality ofelectron guns, and an aperture plate and a secondary electron detectorwhich work associatively with said plurality of electron guns, wherein,in case of the above embodiment, said plurality of electron guns may beplaced side by side in the X direction, so that the inspection for thewidth of 400 μm×(the number of the irradiating systems) may be performedwith a single stroke of movement of the sample in the Y direction.

[0536] According to the 12^(th) embodiment (FIG. 34) of the presentinvention, since the inspection of the sample surface may be performedby moving the sample continuously in the direction orthogonal to thescanning width while covering an extended scanning width (400 μm in theabove embodiment) with a plurality of primary electron beams, thescanning time for the overall surface of said sample may besignificantly reduced. Further, since the plurality of primary electronbeams is employed, the scanning width of each of the electron beams canbe made narrower to reduce the chromatic aberration and thus to reducethe irradiation point E for the sample surface to be smaller, and thespacing between the electron beams can be kept sufficient, as well.Accordingly, this may also reduce any cross talks in the secondaryoptical system.

[0537] Further, since the sample is continuously moved, there should beno time to be wasted for moving the sample in comparison with theconventional electron beam apparatus in which the sample must be heldstationary for scanning the micro region and then the sample is movedfor scanning another micro region. Yet further, employing a plurality ofelectron guns and constructing a plurality of electron beam irradiatingsystems may allow the inspection to be carried out more efficiently.

[0538] According to the twelfth embodiment of the present invention,since the irradiation points of the plurality of primary electron beamshave been arranged two-dimensionally, the distance between theirradiations may be made greater. Also, since the distances between theirradiation points projected onto one axis (the X axis) are all equal,the scanning of the sample may be accomplished leaving no space between.Further, since the EXB has been used to allow the normal-incidence ofthe primary electron beam, the electron beam may be converged to benarrower.

[0539]FIG. 37 is a schematic diagram illustrating a configuration of anelectron beam apparatus 4100 of a thirteenth embodiment according to thepresent invention.

[0540] In FIG. 37, reference numeral 4101 is a single electron gunhaving an integrated cathode for emitting an electron beam used ininspection, 4103 is a condenser lens, 4105 is a multi-aperture plate forforming a plurality of electron beams from the electron beam exited fromthe condenser lens, 4107 is a NA aperture plate arranged at a locationof an enlarged image of an electron beam source formed by the condenserlens, 4111 is a lens for contracting the plurality of electron beamsformed by the multi-aperture plate at a certain reduction ratio to beimaged thereafter on a surface of an object to be inspected or a sample4113, and 4115 is an E×B separator for separating secondary electronspassed through the lens from the primary electrons.

[0541] Herein, the integrated cathode implies the cathode materials suchas single-crystal LaB₆ or the likes whose tip portions having beenprocessed in various shapes.

[0542] Said E×B separator 4115 has such a configuration in which anelectric field and a magnetic field are crossed at a right angle withina plane orthogonal to the normal line of the sample (the upper directionon paper), and has been adapted such that the primary electrons areadvanced straight forward depending on the relationship among theelectric filed, the magnetic field and the primary electron energy. Theapparatus further comprises a deflector 4117 for deflecting all togetherthe plurality of electron beams formed by the multi-aperture plate 4105to scan the inspection region on the sample 4113, a magnifying lens 4119of a secondary optical system, a deflector 4121 for synchronizing withthe deflector 4117 of the primary optical system and for guiding thesecond electrons from the incident points of respective beams passedthrough those apertures 4105 a, 4105 b, 4105 c and 4105 d of themulti-aperture plate 4105 to enter the corresponding detectorsregardless of the scanning of the sample, a multi-aperture plate 4123 ofthe secondary optical system having a plurality of apertures 4123 a,4123 b, 4123 c and 4123 d respectively corresponding to those aperturesof the multi-aperture plate of the primary optical system, and anelectron multiplier tube 4125 for generating a detection signaldepending on the quantity of the entered electrons in the group ofdetectors arranged behind said multi-aperture plate.

[0543] Referring to the electron beam apparatus 4100 of FIG. 37, theelectron beams delivered from the electron gun 4101 are converged by thecondenser lens 4103 and are irradiated onto the apertures 4105 a-4105 dof the multi-aperture plate 4105 for forming a multi-beam. The electronbeams passed through each of the apertures 4105 a, 4105 b, 4105 c and4105 d form a crossover at an aperture location of the NA aperture plate4107 for determining the numerical aperture of the primary opticalsystem. The electron beams after passing through the crossover are madeto form a crossover image on the main field of the objective lens 4111by the condenser lens 4109. Herein, NA is an abbreviation for theNumerical Aperture.

[0544] The aperture image for each of the apertures of themulti-aperture plate 4105 is imaged at first on the main field of theE×B separator 4115 by the condenser lens 4109 and then on the surface ofthe sample 4113 by the objective lens 4111.

[0545] On the other hand, the secondary electrons emanated from thesample are separated from the primary electrons by the E×B separator4115 to be deflected toward the secondary optical system, and magnifiedby the magnifying lens 4119 of the secondary optical system and thenpass through the apertures of the multi-aperture plate 4123 to bedetected by the group of detectors arranged behind said multi-apertureplate.

[0546] In this regard, since the value representative of the currentdensity of the electron beam emitted from the electron gun 4101 is thegreatest for that directed to the central aperture 4105 d of the multiaperture plate 4105 d and said value sequentially decreases in order of4105 c, 4105 b and 4105 a as being more distant from the optical axis,therefore there might be difference in beam currents on the surface ofthe sample 4113 depending on the location thereon.

[0547] In order to deal with this phenomenon, in one embodiment, thesize of the apertures 4105 a-4105 d of the multi-aperture plate 4105 maybe finely adjusted such that the apertures in the vicinity of theoptical axis are made smaller and the apertures are made largergradually as they are distant from the optical axis, so that the beamcurrents passed through the respective apertures may be made equal forall of the beams on the surface of the sample 4113. To accomplish this,a group of detectors for detecting each of the beam currents is mountedon the surface of the sample 4113 so as to detect the current for eachof the beams.

[0548] There is also suggested another method to deal with the aboveproblem, in which the position along the optical axis of the NA apertureplate 4107 for determining the numerical aperture of said primaryoptical system is set to a position offset toward the electron gun 1from the Gaussian image field (focal point of the paraxial beam) for themagnified image of the electron beam source formed by the lens of theprimary optical system. This attempts to use the fact that the positionof the crossover formed by the condenser lens 4103 depends on thespherical aberration of the lens, that is, the crossover position (theposition along the optical axial direction) may be different for each ofthe beams passed through each of the apertures of the multi-apertureplate 4105.

[0549] For example, the position of the crossover to be formed by thebeam from the aperture 4105 a is equivalent to the position 4108 a,while the position of the crossover to be formed by the beam from theaperture 4105 c is equivalent to the position 4108 c. That is, theGaussian image field for the electron source formed by the lens of theprimary optical system is at the farthest location from the NA apertureplate 4107.

[0550] Accordingly, if the NA aperture plate 4107 is displaced from theGaussian image field position toward the electron gun 1 so as to beplaced in a position of the crossover formed by the beam passed throughthe outermost aperture 4105 a of the multi-aperture plate 4105, then forthe beam having passed through the aperture 4105 a, the current densitythereof may be greater when passing through the aperture 4107 withoutthe passing thereof being limited, while the current density of the beamhaving passed through the aperture 4105 c adjacent to the optical axismay be lower with the passing rate thereof being limited, so that theununiformity in the intensities or beam currents on the surface of thesample 4113 could be reduced. It is to be noted that also in this casesimilarly to the previous embodiment, a group of detectors for detectingeach of the beam currents may be disposed in a position for the samplesurface in order to detect the current for each beam passed through eachof the apertures.

[0551] Further, the above problem may be dealt with by combining saidadjustment in aperture size of the multi-aperture plate 4105 with saidadjustment in position of the NA aperture plate 4107 on the opticalaxis.

[0552] Although the above embodiments have been described in the lightof the common goal to uniform the beam currents entering onto thesurface of the sample 4113, there is another problem that the detectionrate of the secondary electron in the secondary optical system actuallyvaries depending on the location whether it is adjacent to or distantfrom the optical axis.

[0553] Accordingly, in still another embodiment of the presentinvention, the ununiformity in the detection rate of the secondaryelectron in the secondary optical system may be corrected by at firstplacing a sample having no pattern in the sample position, thendetecting secondary electrons from said sample with no pattern by thegroup of detectors 4125, and finally determining the location of the NAaperture plate 4107 on the optical axis so that the differences inoutputs from the respective detectors are minimized.

[0554] Further, the ununiformity in the detection rate of secondaryelectrons in the secondary optical system may be corrected by, assimilarly to the above description, at first placing a sample having nopattern in the sample position, then detecting secondary electrons fromsaid sample with no pattern by the group of detectors 4125, and finallyperforming a fine tuning of the aperture size in the multi-apertureplate 4105 of the primary optical system in order to minimize thedifferences in outputs from the respective detectors, such that theaperture size is made smaller for the locations closer to the opticalaxis and made sequentially larger for the locations farther from theoptical axis.

[0555] Still further, the ununiformity in the detection rate ofsecondary electrons in the secondary optical system may be corrected by,as similarly to the above description, at first placing a sample havingno pattern in the sample position, then detecting secondary electronsfrom said sample with no pattern by the group of detectors 4125, andfinally performing a fine tuning of the aperture size of themulti-aperture plate 4123 of the secondary optical system in order tominimize the differences in outputs from the respective detectors, suchthat the aperture size is made smaller for the locations closer to theoptical axis and made sequentially larger for the locations farther fromthe optical axis Yet further, the above problem may be overcome by thecombination of said adjustment of the aperture size in themulti-aperture plate 4105, said adjustment in positioning the NAaperture plate 4107 along the optical axis and said adjustment of theaperture size in the multi-aperture plate 4123 of the secondary opticalsystem. This is accomplished by utilizing the adjusting method in whichthe differences in the outputs from the respective detectors 4125 isminimized by a certain control and calculation techniques, though notillustrated.

[0556] It is to be understood that in the thirteenth embodiment of FIG.37, the evaluation between respective beams is performed in such amanner that the deflector 4117 deflects all the beams at once to scanthe surface of the sample 4133 and the detector concurrently detects thesignals. Also upon causing the scanning motion of the beams, thedeflector 4121 has synchronized with the deflector 4111 to cause thescanning motion of the secondary electrons so that the secondaryelectrons from the respective incident points on the sample surface canenter the corresponding apertures of the multi-aperture plate 4123.

[0557] Applying an electron beam apparatus 4100 of the thirteenthembodiment according to the present invention to the inspection processfor inspecting a wafer in the flow chart of FIG. 12 may accomplish theinspection or measurement of higher throughput and higher accuracy.

[0558] The electron beam apparatus 4100 of the thirteenth embodimentaccording to the present invention is applicable to a variety ofinspections or measurements including a defect inspection, a line widthmeasurement, an alignment accuracy measurement, a voltage contrastmeasurement and the likes for photo mask or reticle and wafer or thelikes (sample).

[0559] According to the electron beam apparatus 4100 of the thirteenthembodiment of the present invention, since an integrated cathode or asingle electron gun has been employed to generate a plurality of beams,the possibility of malfunctions in the electron gun is significantlyreduced in comparison with the case of a plurality of emitters beingused, so that the reliability of the apparatus can be improved. Further,since the apparatus can accomplish the uniformity in the currents forthe respective beams, the inspection and measurement with higheraccuracy and higher throughput may be provided.

[0560] An electron gun such as the thermal field-emission electron gunthat emits electrons toward a limited range may also be used in theelectron beam apparatus 4100 of the thirteenth embodiment.

[0561] According to the electron beam apparatus 4100 of the thirteenthembodiment, since the currents of the respective beams can be madeuniform, the number of beams of the multi-beam can be increased and thusthe multi-beam can be irradiated to cover greater range. Accordingly,the inspection and the measurement may be performed with higherthroughput. Further, the signal strengths of respective beams may bemade almost equal to one another.

[0562] Referring to FIGS. 38 to 41, an electron beam apparatus 4200 ofthe fourteenth embodiment of the present invention will now be describedbelow. FIG. 38 is a schematic diagram of an electron beam apparatus 4200of one embodiment according to the present invention, in which theelectron beam emitted from an electron gun 4201 is converged by acondenser lens 4202 to form a crossover at a point CO. At said crossoverpoint CO is arranged the center of a diaphragm 4204 having an aperturefor determining the NA.

[0563] Beneath the condenser lens 4202 is disposed a firstmulti-aperture plate 4203 having a plurality of apertures, thereby toform a plurality of primary electron beams. Each of those primaryelectron beams formed by the first multi-aperture plate 4203 iscontracted by a demagnifying lens 4205 to be projected onto thedeflection principal plane 4215 of an E×B separator 4206, and afterhaving been focused once on the point 4125, the primary electron beamsare further focused onto a sample 4208 by an objective lens 4207.

[0564] In order not to produce an image field curvature aberrationpossibly caused by the minifying lens 4205 and the objective lens 4207,as shown in FIG. 38, the multi-aperture plate 4203 has a stepped contoursuch that the smaller distance to the condenser lens 4202 at the centralportion thereof is getting greater as toward the peripheral portion.

[0565] Secondary electrons emanated from said plurality of points on thesample 4208 to which the plurality of focused primary electrons isirradiated are attracted by an electric field of the objective lens 4207to be converged narrower, and then focused on a point 4216 before theE×B separator 4206, that is, the point 4216 in the side closer to thesample with respect to the deflection principal plane of the E×Bseparator 4206. This is because each of the primary electron beams hasthe energy of 500 eV on the surface of the sample, while the secondaryelectron beam only has the energy of a few eV. The plurality ofsecondary electron beams emanated from the sample 4208 is deflected bythe E×B separator 4206 to the outside of the axis extending from theelectron gun 4201 to the sample 4208 to be separated from the primaryelectron beams and enters into a secondary optical system.

[0566] The secondary optical system has magnifying lenses 4209 and 4210,and the secondary electron beam passed through those magnifying lenses4209 and 4210 further passes through a plurality of apertures in asecond multi-aperture plate 4211 to be imaged on a plurality ofdetectors 4212. It is to be noted that the plurality of apertures formedthrough the second multi-aperture plate 4211 disposed in front of thedetectors 4212 corresponds to the plurality of apertures formed throughthe first multi-aperture plate 4203 on one to one basis.

[0567] Each of the detectors 4212 converts the detected secondaryelectron beam into an electric signal representative of its intensity.The electric signals thus output from respective detectors are, afterhaving been amplified respectively by an amplifier 4213, received by animage processing section 4214 and converted into image data. Said imagedata is utilized for the evaluation of a defect or line width of thesample.

[0568] That is, since the image processing section 4214 is furthersupplied with a scanning signal for deflecting the primary electronbeam, the image processing section 4214 can display an imagerepresenting the surface of the sample 4208. Comparing this image withthe reference image allows any defects in the sample 4208 to bedetected, and further, the line width of the pattern on the sample 4208can be measured in such a way that the sample 4208 is moved by aregistration to the proximity of an optical axis of the primary opticalsystem and then line-scanned to extract the line width evaluationsignal, which is in turn appropriately calibrated.

[0569] In this regard, it is required to make special arrangements whenthe primary electrons passed through the apertures of the firstmulti-aperture plate 4203 is focused onto the surface of the sample4208, and then the secondary electrons emanated from the sample 4208 areformed into an image on the detector 4212, in order to minimize theaffection by the three aberrations, i.e., the distortion caused by theprimary optical systems, the image field curvature, and the fieldastigmatism. Then the means employed in the fourteenth embodiment of thepresent invention in order to solve the above problem associated withthe aberrations will be described with reference to FIGS. 39 to 41. Itis to be noted that in those illustrations of FIGS. 39 to 41, theprimary and secondary multi-aperture plates 4203 and 4211 have beenillustrated with the size of the apertures, shapes and amounts of offsetthereof being rather exaggerated for better understanding, which are alldifferent from the actual ones.

[0570]FIG. 39 shows a first embodiment of a first multi-aperture plate4203 used in an electron beam apparatus according to the presentinvention, and the multi-aperture plate 4203 of this embodiment is usedwhen there is a distortion aberration of pin-cushion type appeared on asample surface, and in order to compensate for the pincushion typedistortion aberration, the first multi-aperture plate is provided with aplurality of apertures being displaced into a barrel shape. That is,each of the apertures 4221 to 4224 is formed at each of four corners ofa square 4220 centered with the center X of the first multi-apertureplate 4203, i.e., the intersection point where the line extending fromthe electron gun 4201 to the sample 4208 is crossed with the firstmulti-aperture plate 4203.

[0571] The longitudinal and lateral solid lines illustrated in FIG. 39are virtually drawn so as to be parallel with respective sides of saidsquare, and the aperture should be located at each of those intersectionpoints when a plurality of apertures is distributed evenly over themulti-aperture plate 4203. In practice, in order to minimize thedistortion aberration in the primary optical system, each of theapertures will be designed to be located offset from the intersectionpoint of the solid lines toward the center of the first multi-apertureplate 4203 by a certain amount depending on the distance from the centerof the first multi-aperture plate 4203.

[0572]FIG. 40 shows an embodiment of a second multi-aperture plate 4211used in the electron beam apparatus according to the present invention,and this multi-aperture plate 4211 is used to minimize the affection bythe potential distortion of pin-cushion type that might be caused fromthe distortion existing in the secondary optical system. Also in FIG.40, each of the apertures of the second multi-aperture plate 4211 isoffset outwardly from the ideal location in case of uniform distributionthereof, by a certain amount depending on the distance from the centerY.

[0573] The amount of this offset has been calculated from the simulationfor the system comprising the objective lens 4207, the magnifying lenses4209 and 4210, and the E×B separator 4206. Since the outermost aperturenever causes a cross talk even if it is made too large, it may be formedto be large enough. In addition, although each of the multi-apertureplates 4203 and 4211 respectively shown in FIGS. 39 and 40 isillustrated as an embodiment of a single plate which comprises aplurality of apertures formed therethrough, a plurality ofmulti-aperture plates, i.e., two or more pieces of plates may beemployed in the viewpoint of designing the apparatus.

[0574] Concerning to the image field curvature, the first multi-apertureplate 4203 may be made into a shape of stepped contours in sectionalview so as to compensate for the field curvature caused by the primaryoptical system, as described above. The field curvature may possibly becaused even by the secondary optical system, but because of the largersize of the aperture of the second multi-aperture plate 4211 disposed infront of the detectors 4212, the field curvature by the secondaryoptical system could be actually ignored.

[0575] The aberration of field astigmatism occurs because the refractiveindex of the lens in the radial direction is different from that in thecircumferential direction. FIGS. 41A and 41B show respectively a secondembodiment of the first multi-aperture plate 4203 used in the electronbeam apparatus according to the present invention in order to correctthis aberration of field astigmatism, and in the first multi-apertureplate 4203 shown in FIG. 41A, each of the apertures are elongated in theradial direction with respect to the center of the first multi-apertureplate 2403 by a certain amount depending on the distance from saidcenter. Alternatively, in FIG. 41B, each of the apertures is designed tohave a specified shape so that its size in the radial direction and thatin the circumferential direction with respect to the vertical circlecentered with the center of the first multi-aperture plate 4203 varydepending on the distance from the center.

[0576] Reference numeral 4217 in FIG. 38 designates a blankingdeflector, and applying a pulse of narrow width to said blankingdeflector 4217 may form an electron beam having a narrow pulse width.Using thus formed pulse with narrow width allows the potential of thepattern formed in the sample 4208 to be measured with hightime-resolution, and this implies that the electron beam apparatus maybe added with another function of, what is called, a strobe SEM(scanning electron microscope).

[0577] On the other hand, reference numeral 4218 in FIG. 38 designatesan axis-symmetrical electrode, and applying to said axis-symmetricalelectrode 4218 a certain level of potential lower by some 10V than thatof the sample 4208 may drive the secondary electrons emanated from thesample 4208 to flow toward the objective lens 4207 or to return towardthe sample, depending on the potential pertaining to the pattern of thesample 4208. Thereby, the potential contrast on the sample 4208 may bemeasured.

[0578] The electron beam apparatus 4200 according to the fourteenthembodiment of the present invention shown in FIGS. 38 to 40 isapplicable to a defect inspection apparatus, a line width measuringapparatus, an alignment accuracy measuring apparatus, a potentialcontrast measuring apparatus, a defect review apparatus, and a strobeSEM apparatus. Further, the electron beam apparatus according to thepresent invention may be used to evaluate the wafer in the course ofprocessing. Then, the evaluation of the wafer in the course ofprocessing will be described. The manufacturing process of thesemiconductor device has been illustrated in FIG. 12.

[0579] The lithography process, which is a core process in the waferprocessing process of FIG. 12, comprises the resist coating process forcoating with a resist the surface of the wafer having a circuit patternformed therein in the previous process, the exposing process forexposing the resist, the developing process for developing the exposedresist to obtain the pattern of resist, and the annealing process forstabilizing the developed pattern of the resist.

[0580] The electron beam apparatus 4200of the fourteenth embodimentaccording to the present invention may be further used in the waferinspection process of FIG. 12 for inspecting the processed wafer.

[0581] The present invention is not limited to those embodiments. Forexample, in order to accomplish synchronous irradiation againstdifferent locations on the sample 4201, the apparatus may includes aplurality of electron beam irradiation and detection systems eachcomprising the electron gun 4201, the first multi-aperture plate 4203,the primary and the secondary optical systems, the second multi-apertureplate 4211, and the detector 4212, so that a plurality of primaryelectron beams emitted from a plurality of electron guns may beirradiated against the sample and a plurality of secondary electronbeams emanated from the sample may be received by a plurality ofdetectors. Thereby, the time necessary for the inspection or measurementcould be significantly shortened.

[0582] As will be understood from the above description, the electronbeam apparatus of the fourteenth embodiment according to the presentinvention may provide the particular effects as follows:

[0583] 1. Since the apparatus can compensate for the distortionaberration by the primary optical system and reduce the fieldastigmatism as well, therefore extended region may be irradiated with aplurality of beams thus to carry out the defect inspection or the likeof the sample with higher throughput;

[0584] 2. Since the apparatus can compensate for the distortion by thesecondary optical system, as well, therefore there would be no crosstalk even when a plurality of electron beams is used with narrow pitchtherebetween for irradiating and scanning the sample, and further, sinceit can increase the transmittance of the secondary electrons thus toallow the signal having higher S/N ratio to be obtainable, a highlyreliable line width measurement or the like may be provided; and

[0585] 3. Since the primary optical system can form an image on thedeflection principal plane of the E×B separator 4206, the chromaticaberration of the primary electron beam may be reduced, and when theprimary electron beam is formed into a multi-beam, the multi-beam may beconverged narrower.

[0586] An electron beam apparatus 4300 of a fifteenth embodimentaccording to the present invention will now be described with referenceto FIG. 42. FIG. 42 schematically shows an electron beam apparatus 4301of the fifteenth embodiment of the present invention. This electron beamapparatus 4301 comprises a primary optical system 4310, a secondaryoptical system 4330 and an inspection apparatus 4340.

[0587] The primary optical system 4310, which is an optical system forirradiating an electron beam onto the surface of the sample S (samplesurface), comprises: an electron gun 4311 for emitting the electronbeam; an electrostatic lens 4312 for deflecting the electron beamemitted from the electron gun; a multi-aperture plate 4313 having aplurality of small apertures arranged two-dimensionally therethrough(FIG. 42 shows only 4313 a to 4313 e); an electrostatic deflector 4314;an aperture plate 4315; an electrostatic intermediate lens 4316 forconverging the electron beam pass through the aperture plate; a firstE×B separator 4317; an electrostatic intermediate lens 4318 forconverging the electron beam; an electrostatic deflector 4319; a secondE×B separator 4320; an electrostatic objective lens 4321; and anelectrostatic deflector 4322, which are disposed, as shown in FIG. 42,in order with the electron gun 4311 placed in the top so that theoptical axis of the electron beam emitted from the electron gun could benormal to the sample surface SF.

[0588] Therefore, the space between the electrostatic objective lens4321 and the sample S is allowed to be of axial symmetricalconfiguration, so that the electron beam can be converged to benarrower.

[0589] The secondary optical system 4330 comprises an electrostaticmagnifying lens 4331 disposed along an optical axis B, which is inclinedto and separated from the optical axis A near the second E×B separator4320 in the primary optical system 4310, and a multi-aperture plate 4332with a plurality of small apertures arranged two-dimensionallytherethrough (FIG. 42 shows only 4332 a to 4332 e).

[0590] The inspection apparatus 4340 comprises a plurality of detectors4341 each corresponding to each aperture in the multi-aperture plate4332. It is to be noted that the number and the arrangement of theapertures (4332 a or 4332 e) in the multi-aperture plate 4332 correspondrespectively to the number and arrangement of the apertures (4313 a to4313 e) formed in the multi-aperture plate 4313 of the primary opticalsystem. Each component described above may be of well-known one, so thedetailed descriptions about their structures will be omitted.

[0591] Then, an operation of the electron beam apparatus 4300 configuredas above will be described.

[0592] An electron beam C emitted from the single electron gun 4311 isconverged by the electrostatic lens 4312 to be irradiated onto themulti-aperture plate 4313. The electron beam C goes through a pluralityof apertures formed in the multi-aperture plate 4313 to be separatedinto a plurality of electron beams. This plurality of electron beamsforms crossover C1 at the aperture plate 4315 having an aperture. Theelectron beams, after forming the crossover, advance toward the sample Sto be converged by the electrostatic intermediate lens 4316 and anotherelectrostatic intermediate lens 4318 which are disposed on the way, andto be imaged onto a principal plane of the electrostatic objective lens4321, thus to satisfy the Koehler illumination requirement.

[0593] On the other hand, an electron beam D, which forms the respectiveimage of each aperture of the multi-aperture plate 4313, is converged bythe electrostatic intermediate lens 4316 to form an image onto thedeflection principal plane FPI of the first E×B separator 4317, andfurther converged by the electrostatic intermediate lens 4318 to form animage onto the deflection principal plane FP2 of the second E×Bseparator 4320, and finally forms an image onto the sample surface SF.

[0594] The secondary electrons emanated from the sample surface SF areaccelerated and converged by an accelerating electric field for thesecondary electron applied between the electrostatic objective lens 4321and the sample surface SF, pass through the electrostatic objective lens4321, and then image the crossover just at a front side of thedeflection principal plane FP2 of the second E×B separator 4320. Thisimaged secondary electron is deflected by the second separator 4320 tomove along the optical axis B and to enter the electrostatic magnifyinglens 4331. Then the secondary electron is magnified by the electrostaticmagnifying lens 4331 and forms a magnified image at the apertures (4332a to 4332 e) of the multi-aperture plate 4332.

[0595] The sample surface SF and the multi-aperture plate 4332 are in anoptical conjugate relation for the value of 2 eV of the secondaryelectron intensity, so that the secondary electrons emanated from thesample surface by the electron beam pass through respective apertures ofthe aperture plate 4332 corresponding respectively to the respectiveapertures of the aperture plate 4313 and enter the detector 4341 suchthat the secondary electrons emanated from the sample surface SF by theelectron beam having passed through the aperture 4313 a of the apertureplate 4313 pass through the aperture 4332 a of the aperture plate 4332,the secondary electrons emanated from the sample surface SF by theelectron beam having passed through the aperture 4313 b of the apertureplate 4313 pass through the aperture 4332 b of the aperture plate 4332,and the secondary electrons emanated from the sample surface SF by theelectron beam having passed through the aperture 4313 c of the apertureplate 4313 pass through the aperture 4332 c of the aperture plate 4332.

[0596] A space between each of said plurality of electron beams and theelectron beam adjacent thereto can be scanned by controlling theelectron beam so as to cause a deflecting scanning motion exhibiting aprincipal beam trajectory shown by symbol E in FIG. 42, using theelectrostatic deflector 4319 and the second E×B separator 4320. To causethe deflecting scanning motion by the second E×B separator, such avoltage waveform may be applied thereto that satisfies a Wien filterrequirements of the second E×B separator 4320 and is formed bysuperimposing the scanning voltage onto the dc voltage Vw as a centervoltage, wherein the voltage to allow the electron beam to advanceforward is defined as Vw and a magnetic field as Bw, and thereby thetwo-dimensional scanning could be performed when an eight poles typeelectrostatic deflector is employed as the electrodes used to generatethe electric field of the second E×B separator 4320. Therefore it isunnecessary to install a new deflector on an upper side of theelectrostatic object lens 4321, and in addition, both of the E×Bseparator and the electrostatic deflector can be disposed at theiroptimum positions respectively.

[0597] Then, a problem of so-called a beam blur due to a chromaticaberration which is possibly caused by using a single E×B separator inthe prior art, and the solution thereof will be described.

[0598] Generally, in the electron beam apparatus using the E×Bseparator, the degree of aberration is the lowest when the position ofan image of the aperture coincides with the deflection principal planeof the E×B separator for the electron beam. Furthermore, the deflectionprincipal plane of the E×B separator and the sample surface are in aconjugate relationship. Accordingly, when an electron beam with acertain energy width enters into the E×B separator, the quantity ofdeflection of the electron beam with low energy caused by an electricfield increases inversely proportional to the energy, but the quantityof deflection caused by the magnetic field increases inverselyproportional only to the ½th power of the energy.

[0599] On the other hand, in case of the electron beam with high energy,a quantity of deflection of the electron beam along the direction causedby the magnetic field is more than that along the direction caused bythe electric field. In this case, if the electrostatic lens is disposedunder the E×B separator and said lens had no aberration, there wouldoccur no beam blur, but actually the beam blur occurs because the lenshas its aberration. Therefore, with only a single E×B separator beingused, it is impossible to avoid causing the beam blur due to thechromatic aberration when the electron beam has a certain energy width.

[0600] The present invention comprises both of the first and the secondE×B separators 4317 and 4320, and coordinates the electric fields ofsaid two E×B separators so that the directions of the deflection causedby the electric fields of the first E×B separator 4317 and second E×Bseparator 4320 would be reversed each other on the sample surface, andtheir absolute values of the magnitude of deflections would be equal.Accordingly, even when the electron beam has a certain energy width, thechromatic aberration due to the E×B separator can be compensated forbetween the first and the second E×B separators 4317 and 4320.

[0601] When the electron beam apparatus 4301 configured as above is usedto inspect the sample surface for defects, to measure the line width ofthe pattern formed on the sample surface and so on, a sample to beinspected is to be set therein and the electron beam apparatus 4301 isto be operated as described above. In this case, the inspection fordefects can be performed by producing an image data with a scan signalwaveform provided for the electrostatic deflector 4319 and the secondE×B separator 4320 and also with an output signal from the detector 4341for the secondary electron, and by comparing said image data with theother image data produced from another pattern data. Also, the linewidths of the pattern can be measured by the use of signal waveform ofthe secondary electron obtained by scanning the measured pattern at theright angle with the electrostatic deflector 4319 and the second E×Bseparator 4320.

[0602] Furthermore, the alignment accuracy can be evaluated, by forminga pattern produced with a second layer of lithography in the vicinity ofa pattern produced with a first layer of lithography so as for these twopatterns to have the same distance therebetween as that of the electronbeams in a plurality of electron beams of the electron beam apparatus4301, by measuring the distance between these two patterns, and finallyby comparing the measured value with the design value.

[0603] In addition, the image obtained by a scanning type electronmicroscope (SEM) can be displayed on the CRT monitor by connecting theCRT monitor to a part or all of the detector 4341 for the secondaryelectrons and by inputting the data therefrom together with the scanningsignal waveform. This makes it possible for the checker to watch thisSEM image to observe defects for determining the types thereof and thelike.

[0604] Referring to FIG. 42, since the electrostatic deflector 4322 isdisposed co-axially between the electrostatic objective lens 4321 andthe sample surface SF, a potential contrast can be measured by applyingnegative voltage to this electrostatic deflector 4322.

[0605] Again referring to FIG. 42, the short pulse electron beam can beobtained by providing the electrostatic deflector 4314 with the voltageso as not to deflect the electron beam only for a short period and todeflect the electron beam for the rest period in order to make ablanking of the electron beam so that the deflected electron beam isremoved by the aperture 4315. When this short pulse electron beam isentered onto the sample surface SF, so the device on the sample surfaceis made to be in an operating state, then the potential of the patternis measured with good time-resolution, the operation analysis of thedevice on the sample surface can be performed.

[0606]FIG. 43 is a plan view illustrating a condition where a pluralityof pairs of the primary and the secondary optical systems in theelectron beam apparatus configured as described above is arranged on thesample S, in which six pairs of the primary and the secondary opticalsystems 4310 and 4330 are arranged in an array of 2 rows×3 columns inthis embodiment. The circles 4310 a to 4310 f shown with solid linerepresent the maximum outer diameter of the primary optical systems,while the circles 4330 a to 4330 f shown with chain line represent themaximum outer diameter of the secondary optical systems respectively. Inthe present embodiment, the apertures of the multi-aperture plate 4313in the primary optical system 4310 are arranged in an array of 3 rows×3columns, and similarly the apertures of the multi-aperture plate 4332 inthe secondary optical system 4330 are arranged also in an array of 3rows×3 columns.

[0607] A plurality of pairs of respective optical systems is disposedsuch that the optical axis B of each secondary optical system 4330 headstoward the outside of the sample along the alignment direction of thecolumn in order not to interfere with each other. The number of thecolumn is preferably three or four, but it may be less than thesevalues, for example, two, or may be four or more.

[0608] The electron beam apparatus 4300 of the fifteenth embodimentaccording to the present invention also can be used in the waferinspection process of FIG. 12 for inspecting the processed wafers. Whenthe defect inspection method and apparatus of the fifteenth embodimentof the present invention is used in the inspection process, even asemiconductor device having a fine pattern can be inspected with higherthroughput, so that a hundred percent inspection may be carried outwhile allowing the yield of the products to be improved and preventingany faulty products from being delivered.

[0609] According to the fifteenth embodiment of the present invention,the following effects may be expected to obtain.

[0610] (1) Since a plurality of electron beams is employed, thethroughput can be improved.

[0611] (2) Since a plurality of E×B separators is employed and arrangedsuch that the positions of the image of the apertures in the apertureplate coincide with respective positions of the E×B separators and thedirections of the electron beams deflected by the electric fields ofrespective E×B separators are reversed each other on the sample surface,the chromatic aberration possibly caused by the E×B separators can becompensated for and the electron beam can be converged narrower, so thathigher inspection accuracy can be provided.

[0612] (3) Since the electron beam is controlled to make a scanningmotion by superimposing the scanning voltage on the electric field ofthe second E×B separator, the second E×B separator is allowed to workalso as an electrostatic deflector, which means that there is nonecessity to install a new electrostatic deflector above theelectrostatic objective lens 4321 and both of the E×B separator and theelectrostatic deflector can be disposed in their optimum positionsrespectively. This makes it possible both to improve the inspectionefficiency for the secondary electron and to reduce the deflectionaberration, and further to greatly shorten the paths of the secondaryoptical system.

[0613] (4) Since a plurality of pairs of the primary and the secondaryoptical systems in the electron beam apparatus is arranged on thesample, a plurality of samples can be inspected at one time, and therebythe throughput can be improved more.

[0614] (5) since the electrostatic deflector 4322 is disposed co-axiallybetween the electrostatic objective lens 4321 and the sample surface SF,a potential contrast can be measured by applying negative voltage tothis electrostatic deflector 4332.

[0615] (6) When a function for blanking the electron beam is provided tocontrol the voltage of the electrostatic deflector 4314, to generate ashort pulse electron beam, to make the device on the sample surface inan operating state, and to measure the potential of the pattern withgood time-resolution, thereby the operation analysis of the device onthe sample surface can be performed.

[0616]FIG. 44A is a schematic diagram illustrating an electron beamapparatus 4400 according to a sixteenth embodiment of the presentinvention, wherein an electron beam emitted from an electron gun 4401 isfocused by a condenser lens 4402 to form a cross-over at a point 4404. Afirst multi-aperture plate 4403 having a plurality of small apertures isdisposed beneath the condenser lens 4402, and thereby a plurality ofprimary electron beams is formed. Each of the plurality of primaryelectron beams formed by the first multi-aperture plate 4403 iscontracted by a demagnification lens 4405 to be projected onto a point4415. After having been focused onto the point 4415, the primaryelectron beam is focused by an objective lens 4407 onto a sample 4408.The plurality of primary electron beams emitted through the firstmulti-aperture plate 4403 is deflected by a deflector 4419 disposedbetween the demagnification lens 4405 and the objective lens 4407 so asto simultaneously scan a surface of the sample 4408 loaded on an x-ystage 4420.

[0617] In order to eliminate an effect of field curvature aberrationpossibly caused by the reduction lens 4405 and the objective lens 4407,the first multi-aperture plate 4403 is provided with a plurality ofsmall apertures 4433 disposed therein along a circle such that projectedpoints thereof onto x-axis may be equally spaced by Lx, as shown in FIG.44B.

[0618] A plurality of spots on the sample 4408 is irradiated by theplurality of focused primary electron beams, and secondary electronbeams emanated from the plurality of irradiated spots are attracted byan electric field of the objective lens 4407 to be focused narrower,deflected by an E×B separator 4406, and then introduced into a secondaryoptical system. A secondary electron image is focused on a point 4416which is closer to the objective lens 4407 than the point 4415. This isbecause the secondary electron beam has only a few eV of energy whileeach of the primary electron beams has 500 eV of energy on the samplesurface.

[0619] The secondary optical system includes magnifying lenses 4409 and4410, and the secondary electron beam, after having passed through thesemagnifying lenses, passes through a plurality of apertures 4443 formedon a second multi-aperture plate 4411, and is focused on a plurality ofelectron detectors 4412. As shown in FIG. 44B, each of the plurality ofapertures 4443 formed on the second multi-aperture plate 4411 disposedin front of the detectors 4412 corresponds to each of the plurality ofapertures 4433 formed on the first multi-aperture plate 4403 in a mannerof one-by-one basis. Each of the plurality of detectors 4412 is disposedso as to face to each of the plurality of apertures of the secondmulti-aperture plate 4411.

[0620] The detector 4412 converts a detected secondary electron beaminto an electric signal representative of intensity thereof. Theelectric signal output from each of the detectors 4412, after havingbeen amplified respectively by an amplifier 4413, is converted into animage data by an image processing section 4414. Since the imageprocessing section 4414 is further supplied with a scanning signal SSfor deflecting the primary electron beam, the image processing section4414 can generate an image representative of the surface of the sample4408. Comparing this image with a reference pattern allows any defectsof the sample 4408 to be detected. Although being separated duringprocess, a build-up width detecting section 4430 operates in a stage fordetermining an excitation voltage for initial focusing. The operationthereof will be described later.

[0621] Further, a line width of a pattern on the sample 4408 can bemeasured in such a way that the pattern to be measured of the sample4408 is moved by a registration to a proximity of an optical axis of theprimary optical system, and the pattern is line-scanned to extract aline width evaluation signal, which is in turn appropriately calibrated.

[0622] In this regard, when the primary electron beams passed throughthe apertures 4433 of the first multi-aperture plate 4403 are focused onthe surface of the sample 4408, and the secondary electron beamsemanated from the sample 4408 are formed into an image on the detectors4412, much attention should be paid in order to minimize the affectionby the three aberrations, i.e., a distortion caused by the primaryoptical system, an on-axis chromatic aberration and an astigmatism inthe field of view. As for a relation between the spacing among theplurality of primary electron beams and the secondary optical system, ifthe space between respective primary electron beams is determined to begreater than the aberration of the secondary optical system, then thecrosstalk among a plurality of beams can be eliminated.

[0623] The objective lens 4407 is, as shown in FIG. 44C, a uni-potentiallens, wherein a positive high voltage V₀ volt is applied to a centerelectrode of the objective lens 4407 from a power supply 4428 and anexcitation voltage ±ΔV₀, which is low voltage near to earth potential,is applied to an upper and an under electrodes of the objective lens4407 from a power supply 4429 in order to focus the primary electronbeam onto the surface of the sample 4408.

[0624] Each of the electron gun 4401, the deflector 4417 for aligningthe axes, the first aperture plate 4403, the condenser lens 4402, thedeflector 4419, the Wien filter or the E×B separator 4406, the objectivelens 4407, an axisymmetric electrode 4423, and the secondary electrondetector 4412 is accommodated in an optical column 4426 of appropriatesize to configure a complete electron beam scanning/detecting system. Itis to be noted that the initial focusing of the electron beamscanning/detecting system may be executed by fixing the excitationvoltage ΔV₀ to be ×10 Volts while varying the positive voltage V₀.

[0625] AS described above, the electron beam scanning/detecting systemin the optical column 4426 scans a chip pattern on the sample, detectsthe secondary electron beam emanated from the sample as a result ofscanning, and outputs the electric signal representative of theintensity thereof. In practice, since a plurality of chip patterns isformed on the sample surface, a plurality of electron beamscanning/detecting systems (though not shown) each having the sameconfiguration as that shown in FIG. 44A is arranged in parallel so asfor the respective systems to be spaced by integer times of a chip sizeon the sample.

[0626] To further describe the electron beam scanning/detecting system,the electric signal output from the electron detector 4412 is convertedin the image processing section 4414 into a binary information, which isthen converted into the image data. As a result, the image data of acircuit pattern formed on the sample surface is obtained, and theobtained image data is stored in an appropriate storage means andcompared with a reference circuit pattern. Thereby the defect of thepattern formed on the sample or the like can be detected.

[0627] As the reference circuit pattern used to be compared with theimage data representative of the circuit pattern on the sample surface,various kinds of data may be employed. For example, an image dataobtained from a CAD data used to fabricate the circuit patter to whichthe scanning has been applied to generate said image data.

[0628] In the electron beam apparatus shown in FIG. 44A, a value of theexcitation voltage ±×V₀ to be applied to the upper or the underelectrode of the objective lens 4407 is determined under control of acontrol device such as CPU (though not shown) as follows:

[0629] At first, a location where a pattern edge parallel with a firstdirection and another pattern edge parallel with a second directionorthogonal to said first direction exist on a single arbitrary circuitpattern formed on the surface of the sample 4408 is read out, forexample, from the pattern data and is identified.

[0630] Then, the primary electron beam is used by the deflector 4419 andthe E×B separator 4406 to scan the pattern edge parallel with the firstdirection in the second direction; the electric signal representative ofthe intensity of the secondary electron beam emanated as a result of thescanning operation is obtained from the electron detector 4412; and thena build-up width p(μm) of said electric signal is measured in thebuild-up width detection section 4430. Similarly, the primary electronbeam is used by the deflector 4419 and the E×B separator 4406 to scanthe pattern edge parallel with the second direction in the firstdirection; the electric signal representative of the intensity of thesecondary electron beam emanated as a result of the scanning operationis obtained from the electron detector 4412; and then the build-up widthp of said electric signal is measured in the build-up width detectionsection 4430. This operation is repeated at least three times fordifferent voltage values by varying the voltage ±ΔV₀.

[0631] A control device (not shown) produces curves A and B of FIG. 45Abased on the data from the build-up width detection section 4430. Thecurve A shows a relation between the build-up width pμm and each of ±ΔVfor the pattern edge parallel with the first direction. The curve Bshows a relation between the build-up width pμm and each of ±ΔV₀ for thepattern edge parallel with the second direction.

[0632] As shown in the graph of FIG. 45B, the “build-up width R” of theelectric signal is represented as a distance of scanning R(μm) duringwhich the electric signal varies from 12% to 88% of its maximum valuewhen said electric signal is measured by scanning the pattern edgeparallel with the first (or second) direction in the second (or first)direction under the condition where the excitation voltage ±ΔV₀ isfixed.

[0633] The curve A of FIG. 45A shows that the build-up width p isminimum, that is, the build-up is the sharpest when the excitationvoltage ±ΔV₀ is −ΔV₀(x). Similarly, the curve B shows that the build-upwidth is minimum, that is, the build-up is the sharpest when theexcitation voltage ±ΔV₀ is ±ΔV₀(x). Accordingly, the focusing conditionof the objective lens 7, that is, the value of the voltage ±ΔV₀ to beapplied to the upper and the under electrodes is preferably set to beequal to {−ΔV₀(x)+ΔV₀(y)}/2.

[0634] Since the excitation voltage ±ΔV₀ varies only within a range of 0to ±20 Volts, the setting operation of the objective lens 4407 wasactually tried in a manner described above and could be finished in highspeed within 10 micro-seconds, and it took only 150 micro-seconds toobtain the curves A and B of FIG. 45A.

[0635] It is to be apprehended that there is no need to make ameasurement for a number of ±ΔV₀ values, but only −ΔV(1), +ΔV(1) and+ΔV(3) should be set as the three voltage values of ±ΔV₀ to measure thebuild-up width p so as to determine the curves A and B by hyperbolicapproximation, and thereby to determine the minimum values of thebuild-up width, i.e., −ΔV₀(x) and +ΔV₀(y). In this case, the measurementmay be completed within about 45 micro-seconds.

[0636] As described above, the curves A and B of FIG. 45A approximate toquadratic curve or hyperbola. Assuming that the build-up width is p(μm),and the objective lens's voltage ±ΔV₀ is q(volts), the graphs A and Bcan be represented as:

(p ² /a ²)−(q−c)² /B ²=1

[0637] where, a, b and c are constants. When three q (voltage ±ΔV₀)values, q₁, q₂ and q₃, and p (build-up width) values correspondingthereto, p₁, p₂ and p₃ are substituted for the corresponding terms inthe above equation, three equations (1) to (3) can be obtained as below:

(p ₁ ² /a ²)−(q−c)² /b ²=1  (1)

(p ₂ ² /a ²)−(q ₂ −c)/b ²=1  (2)

(p ₃ ² a ²)−(q ₃ −c)/b²=1  (3)

[0638] From these equations, the values of a, b and c can be calculatedand when q=c, the minimum value may be obtained.

[0639] As described above, the excitation voltage ΔV₀(x) to be appliedto the objective lens for the pattern edge parallel with the firstdirection, which provides the smallest build-up width p, can bedetermined by three lens conditions. Quite similarly, the excitationvoltage ΔV₀(y) to be applied to the objective lens for the pattern edgeparallel with the second direction can be determined.

[0640] As is shown in FIG. 45A by the curves A and B, the build-up widthobtained when the pattern edge extending along the first direction isscanned in the second direction is typically different from thatobtained when the pattern edge extending along the second direction isscanned in the first direction. In this case, it is necessary to performan astigmatic correction by further installing an eight-pole astigmaticcorrecting lens 4421 (see FIG. 44) and adjusting the voltage to beapplied to said lens 4421 so that the build-up of the electric signalfrom the electron detector 4415 generated by scanning the pattern edgesin the first and the second directions may be made further smaller. Whenthere are little astigmatism, since either of ΔV₀(x) or ΔV₀(y) isrequired to be determined, only either of curve A or B may bedetermined.

[0641] As described above, after the focusing operation of the electronbeam scanning/detecting system having been finished, the process forevaluating the sample 4408 will be set about. In the present method,since the focusing condition is determined by using not an optical Zsensor but the electronic optical system, it is advantageous in that thecorrect focusing condition may be determined even if the sample ischarged with electricity.

[0642] When other optical column (not shown) each having the similarconfiguration to that of the optical column 4426 including the electronbeam scanning/detecting system are arranged parallel with the opticalcolumn 4426 so as for each of them to be spaced from each other by adistance of integer times of the chip size on the sample 4408, it isnecessary to perform the focusing operation in each optical column so asfor the primary electron beam to be focused on the sample. Such afocusing operation, however, can be performed almost simultaneously, sothe throughput budget does not take much.

[0643] Then a semiconductor device manufacturing method according to thepresent invention will now be described. The semiconductor devicemanufacturing method according to the present invention is performed byusing the electron beam apparatus described above in the semiconductordevice manufacturing method shown in FIGS. 12 and 13 described above.

[0644] In the semiconductor device manufacturing method according to thepresent invention, any defects on the wafer can be surely detected sincean image with reduced distortion and blur may be obtained even for thesemiconductor device with finer pattern by using the electron beamapparatus having described with reference to FIG. 44 not only in aprocess in the course of processing (wafer inspection process) but alsoin a chip inspection process for inspecting the finished chip.

[0645] Using the electron beam apparatus according to the presentinvention in the wafer inspection process and the chip inspectionprocess of FIG. 12 allows even the semiconductor device with finerpattern to be inspected with high throughput, which allows a hundredpercent inspection and an improvement in yield of the products, and alsoallows to prevent the defective product from being delivered.

[0646] The electron beam apparatus 4400 according to the sixteenthembodiment of the present invention provides such operational effects asbelow:

[0647] (1) Since no optical sensor is necessary for measuring a heightof the sample surface, spacing between the objective lens and the samplecan be designed under optimum conditions with only electronic opticalsystem;

[0648] (2) Since the focusing operation of the electron beamscanning/detecting system can be performed only with the adjustment inlow voltage, the setting time may be made shorter, that is, the focusingoperation can be performed in short time;

[0649] (3) If desired, the astigmatic correction may be performed inshort time during focusing operation; and

[0650] (4) Since the sample in the course of process can be evaluated inshort time, the yield of the device manufacturing may be improved.

[0651] Now, a description will be given regarding an electron beamapparatus 4500 of Embodiment 18 with reference to FIGS. 46 and 47. FIG.46 schematically illustrates an electron beam apparatus 4501 ofEmbodiment 18. The electron beam apparatus 4501 comprises a primaryoptical system 4510, a secondary optical system 4530, and a detectiondevice 4540. The primary optical system 4510 is composed of an opticalsystem for irradiating the surface of a sample S with an electron beam.

[0652] This optical system comprises an electron gun 4511 for emittingelectron beams, an electrostatic lens 4513 for demagnifying the electronbeams emitted from the electron gun, a first aperture plate 4514 with aplurality of small apertures formed in a two-dimensional arrangement(only small apertures 4514 a to 4514 i, inclusive, being illustrated inFIG. 46), an open aperture 4515, an electrostatic lens 4516 fordemagnifying the electron beams passed through the first aperture plate,an electrostatic deflector 4517, an E×B separator 4518, and anelectrostatic objective lens 4519. As shown in FIG. 46, these componentsare arranged in such a manner that the electron gun 4511 is disposed ontop of all the other components in the order as shown in FIG. 46 andthat the optical axis A of the electron beams emitted from the electrongun is disposed so as to extend in the direction perpendicularly to thesample S. Inside the electron gun 4511, there is formed a projectionportion 4512 that is made of a single crystal, LaB₆ cathode, polishedinto a form having a number of projections.

[0653] The first aperture plate 4514 is provided with a plurality of thesmall apertures on its circumference, as shown in FIG. 47, so as for theimages projected in the X-direction to be disposed at an equal intervalLx, in order to undergo no influence of an aberration caused by acurvature of the image plane of the electrostatic lenses 4513 and 4516as well as the electrostatic objective lens 4519.

[0654] The secondary optical system 4530 includes a first electrostaticmagnifying lens 4531, an open aperture 4532, a second electrostaticmagnifying lens 4533, and a second aperture plate 4534 with a pluralityof small apertures (only small apertures 4534 a-4534 i, inclusive, beingillustrated in FIG. 46) disposed in a two-dimensional arrangement. Thesecomponents are arranged in the above order along the optical axis Binclined with respect to the optical axis A in the vicinity of the E×Bseparator 4518.

[0655] The detection device 4540 is provided with a detector 4541 foreach aperture of the second aperture plate 4534. The number andarrangement of the small apertures (as indicated by broken line in FIG.47), e.g., 4534 a to 4534 e, of the second aperture plate 4534 areadjusted so as to agree with the number and arrangement of the smallapertures (as indicated by solid line in FIG. 47), e.g., 4514 a to 4514e, of the first aperture plate 4514. Each of the structuring elementsmay be known and its detailed description will be omitted herein.

[0656] Then, a description will be given regarding a standard mode inthe electron beam apparatus 4500 having the configuration as describedabove. In this electron beam apparatus, electron beams C emitted fromthe number of the projection portions 4512 of the single electron gun4511 are converged with the electrostatic lens 4513 and then irradiatedon the first aperture plate 4514. The electron beams C are formed intomulti-beams by allowing the electron beams C to pass through the smallapertures (e.g., 4514 a to 4514 e) formed in the first aperture plate4514. The multi-beams form each a crossover image C1 by means of theopen aperture 4515. The crossover multi-beams travel toward the sample Sand converged with the electrostatic intermediate lens 4516 disposed onthe way, followed by forming an image on the main plane of theelectrostatic objective lens 4519 so as to meet with Keller'sillumination conditions. The multi-beams with the image formed thenproduce a reduced image on the sample and the surface of the sample isthen scanned with the electrostatic deflector and a deflector of the E×Bseparator 4518.

[0657] The secondary electron beams emitted from the sample S areaccelerated and converged by the accelerating electric field for thesecondary electrons, applied between the electrostatic objective lens4519 and the sample S, followed by passing through the electrostaticobjective lens 4519 and entering into the first electrostatic magnifyinglens 4531 after being deflected with the E×B separator 4518 so as totravel along the optical axis B. The secondary electron beams are thenmagnified with the first electrostatic magnifying lens 4531 and form acrossover image C2 on the open aperture 4532. The secondary electronbeams that formed the image are then magnified with the electrostaticmagnifying lens 4533 and form an image at each of the small apertures(e.g., 4534 a to 4534 e) of the second aperture plate 4534. Themagnification factor of the secondary optical system can be decided bythe two electrostatic magnifying lenses 4531 and 4533.

[0658] As shown in FIG. 47, the secondary electron beams emitted at thesurface of the sample by means of the electron beams scanning aredelivered to the detector 4541 after passage through each of the smallapertures of the second aperture plate 4534 corresponding to therespective small apertures of the first aperture plate 4514. Morespecifically, for example, the secondary electron beams emitted from thesample S by means of the electron beams passed through the smallaperture 4514 a of the first aperture plate 4514 is delivered to thedetector 4541 through the corresponding small aperture 4534 a of thesecond aperture plate 4534.

[0659] Likewise, the secondary electron beams emitted from the sample Sby means of the electron beams passed through the small aperture 4514 bof the first aperture plate 4514 is then delivered on the detector 4541through the corresponding small aperture 4534 b of the second apertureplate 4534. The electron beam emitted from the sample S by means of theelectron beams passed through the small aperture 4514 c of the firstaperture plate 4514 is likewise delivered to the detector 4541 insubstantially the same manner as the secondary electron beams emittedfrom the sample S by means of the electron beams passed through thecorresponding small aperture 4514 a or 4514 b of the first apertureplate 4514. The remaining secondary electron beams can be said true.

[0660] In order to allow changes from the standard mode to the highresolution mode, it is required to alter a scanning width and amagnification of an image. The scanning width can be altered byadjusting a degree of sensitivity to deflection per bit of theelectrostatic deflector 4517 and the deflector of the E×B separator4518. If the scanning width would become narrower than that of thestandard mode, however, a gap of scanning may be caused to happenbetween each of the beams of the multi-beams. Further, in the secondaryoptical system, the intervals of the beam images result in disagreementwith the intervals of the detectors.

[0661] The problem with the formation of the scanning gap between thebeams can be solved by varying the rate of reduction from the firstaperture plate 4514 to the sample S so as to correspond with a variationin a dimension of a pixel by subjecting the electrostatic lens 4516 andthe electrostatic objective lens 4519 to zoom operation. The Keller'sillumination conditions to form the crossover image C1 on the principalplane of the electrostatic objective lens 4519 are adjusted so as to besatisfied in the standard mode only, but not in the high-resolutionmode.

[0662] As the measure against the problem that the interval of the beamimages fails to agree with the dimension of the interval between thedetectors in the secondary optical system, the principal ray of thesecondary electrons emitted from each of the multiple beams from thesample is delivered to the corresponding small aperture of the secondaryaperture plate by fixing the position and dimension of the aperture 4532of the secondary optical system and varying an excitation voltage of theelectrostatic magnifying lens 4533. In other words, the magnificationfactor is adjusted by the electrostatic magnifying lens 4533 of thesecondary optical system so as to comply with the conditions forfocusing the crossover image on the aperture 4532. Further, the samplecan be evaluated on the basis of two kinds of dimensions of the image bysubjecting the rate of reduction of the multi-beams to zoom operationsof the electrostatic lens 4516 and the electrostatic objective lens 4519as well as by altering the rate of magnification of the electrostaticmagnifying lenses 4531 and 4533 of the secondary optical system inassociation with the zoom operations.

[0663] As to the relation between a demagnification ratio of themulti-beam in the primary optical system and a magnification ratio inthe electrostatic lens of the secondary optical system, in specific,assuming that in FIG. 46, a dimension between the apertures (forexample, the distance between 4514 a and 4514 b) is 1 mm and thedemagnification ratio of the multi-beam in the primary optical system is1/100, the distance between the beam going out of the aperture 4514 aand that out of the aperture 4514 b is 10 μm. When the magnificationratio of the secondary optical system is 500, the distance between theapertures 4534 a and 4534 b is 5 mm.

[0664] When the demagnification ratio of the multi-beam in the primaryoptical system is changed to be 1/200, the distance between theapertures 4534 a and 4534 b may be kept to be 5 mm by setting themagnification ratio of the secondary optical system to be 500×2=1000,and thereby the secondary electron can be detected without changing thedistance between the apertures 4534 a and 4534 b. This feature isadvantageous in that the beam dimensions, the beam current or thescanning width can be changed by varying the demagnification ratio ofthe multi-beam in the primary optical system. This allows to perform theevaluation with high resolution at the sacrifice of low throughput, orthe evaluation with high throughput at the sacrifice of low resolution.

[0665] Further, the cross-over image is formed on the principal plane ofthe objective lens in a mode with high throughput and low resolution. Inspecific, for example, in the apparatus having a mode with theresolution of 50 nm and the throughput of 8.8 min/cm² and another modewith the resolution of 100 nm and the throughput of 33 sec/cm², thecross-over image is set on the principal plane of the objective lens inthe former mode.

[0666] The electron beam apparatus 4500 according to the seventeenthembodiment of the present invention (FIG. 46) may be preferably appliedto the semiconductor device manufacturing method shown in FIGS. 12 and13. That is, using the defect inspection method and apparatus accordingto the eighteenth embodiment of the present invention in the inspectionprocess of the present manufacturing method allows even thesemiconductor device with finer pattern to be inspected with highthroughput, which allows a hundred percent inspection and an improvementin yield of the products, and also allows to prevent the defectiveproduct from being delivered.

[0667] The electron beam apparatus 4500 of the embodiment 17 accordingto the present invention can demonstrate the effects as follows:

[0668] (1) As an image of an optional magnification can be formedwithout causing any scanning gap, both of the standard mode and thehigh-resolution mode can be used.

[0669] (2) Even if the rate of magnification would be changed, the imagedimension can be adjusted so as to substantially correspond to the beamdimension.

[0670] (3) In the standard mode, the Keller illumination conditions ofthe primary optical system can be met. On the other hand, even in thehigh-resolution mode, a deviation from the Keller's illuminationconditions of the primary optical system can be rendered small and anincrease in aberration is not caused so much.

[0671] (4) As the aperture is disposed in the position in which thesecondary electrons emitted from the sample in the directionperpendicular to the sample plane crosses the optical axis of thesecondary optical system, the secondary electrons having no differencein strength between the multi-beams can be detected even if the modewould be changed.

[0672] Then, a description will be given regarding the electron beamapparatus 5000 according to Embodiment 19 of the present invention withreference to FIGS. 48 and 49, which schematically illustrate an electronbeam apparatus 5001 of Embodiment 19. The electron beam apparatus 5000comprises a primary electron-optical system (hereinafter referred to as“the primary optical system”) 5010, a secondary electron-optical system(hereinafter referred to as “the secondary optical system”) 5020, and adetection system 5030.

[0673] The primary optical system 5010 is an optical system thatirradiates the surface of an object of evaluation (hereinafter referredto as “the sample”) S such as a wafer or the like with an electron beam,which comprises an electron gun 5011 for emitting electron beams, orelectron beams, a condenser lens 5012 for converging the primaryelectron beams emitted from the electron gun 5011, a firstmulti-aperture plate 5013 with a plurality of apertures formed therein,a reducing lens 5014, an E×B separator 5015, and an objective lens 5016.These elements are disposed in this order, as shown in FIG. 48, with theelectron gun 5011 disposed on top. Reference numerals 5017 and 5018designate each a deflector for scanning the primary electron beams andreference numeral 5019 designates an axially symmetrical electrode.

[0674] The secondary optical system 5020 comprises magnifying lenses5021 and 5022 and a second multi-aperture plate 5023, which are disposedalong the optical axis inclined with respect to the optical axis of theprimary optical system. The detection system 5030 includes a detector5031 disposed for each of the apertures 5231 of the secondmulti-aperture plate 5023 and an image forming portion 5033 connected toeach of the detectors through an amplifier 5032. For the primary opticalsystem 5010, the secondary optical system 5020 and the detection system5030, there can be used those having the structure and function of eachof the structuring elements known to the art, so that a more detaileddescription of those structuring elements is omitted herefrom. Moreover,the apertures 5131 of the first multi-aperture plate 5013 are formed soas to correspond to the apertures 5231 of the second multi-apertureplate 5023. In FIG. 49, the apertures 5131 as indicated by solid lineare illustrated to be smaller in size than the apertures 5231 asindicated by broken line.

[0675] The sample S is detachably held on a stage device 5040 through aholder 5041 by means of a conventional technique, and the holder 5041 isheld with a XY-stage 5042 so as to be movable in the orthogonaldirection.

[0676] The electron beam apparatus 5001 is further provided with aretarding voltage applying device (hereinafter referred to as “theapplying device”) 5050 electrically connected to the holder 5041, and acharging state investigating and retarding voltage determining system(hereinafter referred to as “the investigating and determining system”)5060. The investigating and determining system 5060 comprises a monitor5061 electrically connected to the image forming portion 5033, anoperator 5062 connected to the monitor 5061, and a CPU 5063 connected tothe operator 5062. Further, the CPU 5063 is arranged to supply a signalto the applying device 5050 and the deflector 5017.

[0677] Then, a description will be given regarding the operations of theelectron beam apparatus of embodiment 20. The primary electron beamemitted from the electron gun 5011 is converged with the condenser lens5012 forming a crossover image at a point P1. The electron beam passedthrough the aperture 5131 of the first multi-aperture plate 5013 isconverted into plural primary electron beams by means of the pluralapertures 5131. The primary electron beams formed by the firstmulti-aperture plate 5013 are reduced with the reducing lens 5014 andprojected on a point P2. After focused on the point P2, the primaryelectron beams are then focused on the surface of the sample S with theobjective lens 5016. The plural primary electron beams are thendeflected with the deflector 5018 disposed between the reducing lens5014 and the objective lens 5016 so as to concurrently scan the topsurface of the sample.

[0678] In order to eliminate the influences from the aberration causedby the field curvature of each of the reducing lens 5014 and theobjective lens 5016, the plural apertures 5131 and 5231 of the first andsecond multi-aperture plates 5013 and 5016 are disposed on thecircumference around the optical axis of the optical system,respectively, and the distance Lx of each of the adjacent apertures isarranged so as to become equal to each other, as shown in FIG. 49, whenprojected in the X-direction.

[0679] The plural primary electron beams focused are irradiated on thepoints on the sample S, and the secondary electrons emitted from thepoints thereof are converged slenderly by the attraction of the electricfield of the objective lens 5016 and then deflected with the E×Bseparator 5015, followed by entering into the secondary optical system5020. The images of the secondary electrons are focused on a point P3closer to the objective lens than the point P2. This is because thesecondary electron beam has only the energy of several eV, compared witheach of the primary electron beams having an energy as high as 500 eV.

[0680] The image of the secondary electron is allowed to form an imageon the detector 5031 disposed for each of the apertures 5231 of thesecond multi-aperture plate 5023 by means of the magnifying lenses 5021and 5022. Therefore, the secondary electron image is detected with therespective detectors 5031. Each of the detectors 5031 converts thesecondary electron image detected into an electric signal representativeof its intensity. The electric signal generated from each of thedetectors is amplified with the corresponding amplifier 5032 anddelivered to the image forming portion 5033 where the electric signal isconverted into an image data. To the image forming portion 5033 is fed ascanning signal for deflecting the primary electron beams, and an imageforming portion displays an image representing the plane of the sampleS. This image is compared with the reference pattern to detect a defectof the sample S.

[0681] Further, the sample S is transferred to the position close to theoptical axis of the primary optical system 5010 by means of registrationand the line scanning, or scanning, is performed on the surface of thesample to extract a signal for use in evaluating the line width of thepattern formed on the surface thereof. By calibrating the signals in anappropriate way, the line width of the pattern can be measured.

[0682] It is to be noted herein that it is necessary to draw a specialattention to minimize the influences caused by three aberrationsincluding distortion caused by the primary optical system, axialchromatic aberration, and field astigmatism, when the primary electronbeams passed through the apertures of the first multi-aperture plate5013 are focused on the top surface of the sample S and the secondaryelectron beams emitted from the sample S are focused to form an image onthe detector 5031.

[0683] Moreover, a crosstalk among the plural beams can be eliminated bybringing the distance between the primary electron beams to beirradiated on the sample into a relationship with the secondary opticalsystem in such a manner that each the distances among the primaryelectron beams to be irradiated on the sample is apart by the distancelarger than the aberration of the secondary optical system.

[0684] The image data converted with the image forming portion 5033 isdisplayed as an image with a display unit 5061 of the investigating anddetermining device 5060. The image displayed can be evaluated by theoperator 5062. The operator 5062 constitutes a charging stateinvestigating unit in this embodiment adapted to investigate a chargingstate on the basis of the image. The result of investigation is inputtedinto the CPU 5063 to set the retarding voltage to an optimal value. TheCPU constitutes a retarding voltage determining unit in this embodiment.

[0685]FIG. 50A is a diagram for explaining an evaluation location and anevaluation method of charging. A peripheral portion of a memory cellboundary 5102 of a chip 5100 is a peripheral circuit section of lowdensity region. An inside thereof is a memory cell section of highdensity region. Accordingly, A1 and A2 provide an image of the boundaryregion, and A3 and A4 provide an image of the memory cell section. A twodot chain line and a dashed line show the boundary on which the densitychanged greatly.

[0686] More specifically, the evaluation is performed on a location ofthe sample to be evaluated, which is likely to undergo an influence fromthe charging, that is, a corner portion of a memory cell 5101 of a chip5100 formed on the surface of a wafer as the sample, as shown in FIG.50A. In other words, (1) distortion amounts 5103 and 5104 of a patternof a memory cell boundary 5102 at the corner portion may be measured or(2) a contrast of the signal intensity obtained upon scanning thepattern at the corner portion of the memory cell in a way of crossingthe pattern (as indicated by arrows A1 and A2) may be compared withcontrasts 5106 and 5108 (as indicated by broken lines in FIG. 50B) ofthe strength of the signals obtained by displaying solid lines 5105 and5107, respectively, as shown in FIG. 50B, and scanning the pattern atthe central portion of the chip in the directions as indicated by arrowsA3 and A4.

[0687] Voltage of plural values is applied to the retarding voltageapplying device 5050 while measuring the distortion amounts 5103 and5104 or the contrasts 5105, 5107 and 5106, 5108 whenever the voltage isapplied, thereby conducting evaluations to the effect that thedistortion amount 5103 or 504, whichever smaller, has a smallerinfluence from the charging state. Likewise, it is evaluated that thecontrast value 5105 or 5107 at the corner portion, whichever closer tothe contrast value at the central portion, has a smaller influence ofthe charging state.

[0688] If the retarding voltage having a good charging state could befound, the value is applied to the applying device 5050 through the CPU5063 and the sample, i.e., the wafer, is evaluated on the basis of thisvalue. Moreover, a beam current may be made small when using a samplethat can reduce its charging state at a small beam current.

[0689] Thus, an image-forming around the boundary where the patterndensity on the sample greatly changes emphasizes an effect of charging,which facilitates an evaluation of charging, and makes it easy to findthe landing voltage for hardly causing the charging.

[0690] The electron beam apparatus 5000 of Embodiment 19 (FIG. 48) ofthe present invention can be preferably used for the method for themanufacturing of the semiconductor device as shown in FIGS. 12 and 13.When the defect inspection method and the defect inspection apparatusaccording to Embodiment 19 of the present invention are used for theinspection step of the manufacturing method, the semiconductor devicehaving a fine pattern can also be inspected at a high throughput so thatall the number of products can be inspected. Further, a yield ofproducts can be improved and a shipment of defective products can beprevented.

[0691] The Embodiment 19 (FIG. 48) of the present invention candemonstrate the effects as follows:

[0692] (a) A high throughput can be achieved at a value close to themultiple proportional to the number of electron beams, and the value ofthe throughput may be improved by several times.

[0693] (b) An evaluation at a higher reliability can be achieved becausethe evaluation of the wafer can be performed in a state in which thecharging state is smallest.

[0694] (c) A more accurate result of evaluation can be obtained becausethe charging performance can be evaluated on the basis of an actualimage, without measurements of various currents.

[0695]FIG. 51 shows an E×B separator 6020 of Embodiment 20 according toan embodiment of the present invention. The E×B separator 6020 comprisesthe electrostatic deflector and the electromagnetic deflector. FIG. 51is a view in section, as taken along an x-y plane crossing the opticalaxis (the axis perpendicular to the plane of this drawing: z-axis) at aright angle. Further, the x-axial direction intersects with the y-axialdirection at a right angle.

[0696] The electrostatic deflector is provided with a pair of electrodes(electrostatically deflecting electrodes) 6001 in a vacuum container tocreate the electric field in the x-axial direction. Theelectrostatically deflecting electrodes 6001 are mounted on a vacuumwall 6003 of the vacuum container through an insulating spacer 6002. Thedistance D between these electrodes is set to become smaller than they-axial length 2L of the electrostatically deflecting electrode 6001.This setting can make the range of the uniform strength of the electricfield formed around the z-axis relatively large. Ideally, the rangewhere the strength of the electric field is uniform can be made largerif the distance D is smaller than L, i.e., D <L.

[0697] In other words, as the electric field strength is irregular inthe range of D/2 from the edge of the electrode, the range where theelectric field strength is nearly uniform is located in the range of2L-D at the central portion, excluding the irregular edge region.Therefore, in order to allow the range of the uniform electric fieldstrength to exist, it is necessary to make 2L larger than D, i.e., 2L>D.Moreover, by setting to be L>D, the range of the uniform electric fieldstrength can be rendered larger.

[0698] Outside the vacuum wall 6003 is disposed the electromagneticallydeflecting device for forming a magnetic field in the y-axial direction.The electromagnetically deflecting device is provided withelectromagnetic coils 6004 and 6005, which can form the magnetic fieldin the x-axial and y-axial directions, respectively. Although only themagnetic coil 6005 can create the y-axial magnetic field, the magneticcoil 6004 for forming the x-axial magnetic field may be additionallydisposed in order to improve the orthogonality between the electricfield and the magnetic field. In other words, the orthogonality betweenthe electric field and the magnetic field can be made better byoffsetting the magnetic field component in the +x-axial direction formedby the magnetic coil 6005 for the magnetic field component in the−x-axial direction formed by the magnetic coil 6004.

[0699] As the magnetic coils 6004 and 6005 for forming the magneticfields are mounted outside the vacuum container, each of them may bedivided into two sections which may be mounted on the vacuum wall 6003from the both sides and integrally fastened at portions 6007 with screwsor other fastening tools.

[0700] The outermost layer 6006 of the E×B separator may be composed ofa permalloy or ferrite yoke. The outermost layer may be divided into twosections, like the magnetic coils 6004 and 6005, and the two sectionsmay be mounted on the outer periphery of the magnetic coil 6005 from theboth sides and integrally fastened at portions 6007 with screws or thelike.

[0701]FIG. 52 shows a section of an E×B separator of Embodiment 21according to the present invention, the section extending in thedirection orthogonal to the optical axis (z-axis) thereof. The E×Bseparator of Embodiment 21 differs from that of Embodiment 20, as shownin FIG. 51, that six electrostatically deflecting electrodes 6001 aredisposed. To the electrostatically deflecting electrodes 6001 are fedvoltage, k×cos θi (where k is constant and θi is an optional angle)proportional to cos θi, when the angle of the line connecting the centerof each of the electrodes and the optical axis (z-axis) with respect tothe direction of the electric field (x-axial direction) is set to θi(where i=0, 1, 2, 3, 4, 5).

[0702] In Embodiment 21 as shown in FIG. 52, too, the electric field canbe formed in the x-axial direction only, so that the coils 6004 and 6005for forming the magnetic fields in the respective x-axial and y-axialdirections are disposed to correct the orthogonality.

[0703] Embodiment 21 can make the range of the uniform electric fieldstrength larger than Embodiment 20 as shown in FIG. 51.

[0704] In Embodiments 20 and 21 as shown in FIGS. 51 and 52,respectively, a coil of a saddle type may be used for forming themagnetic field. It is also possible to use a coil of a toroidal type asa coil for forming the magnetic field.

[0705]FIG. 53A is a schematic view of an electron apparatus 6000 (adefect inspection apparatus) for which the E×B separator of Embodiments20 and 21 can be adopted to separate the secondary electron beams fromthe primary electron beams. In FIG. 53A, the electron beams emitted froman electron gun 6021 are converged with a condenser lens 6022 to form acrossover image at a point 6024.

[0706] Beneath the condenser lens 6022 is disposed a firstmulti-aperture plate 6023 having a plurality of apertures to form aplurality of primary electron beams. The plural electron beams formedare each reduced with a reducing lens 6025 and projected on a point6035. After focused on the point 6035, the primary electron beams arethen focused with an objective lens 6027 on a wafer 6028 as a sample.The primary electron beams from the first multi-aperture plate 6023 arethen deflected with a deflector disposed between the reducing lens 6025and the objective lens 6027 so as to simultaneously scan the surface ofthe wafer 6028.

[0707] In order to cause no aberration due to the curvature on an imageplane of the reducing lens 6025 and the objective lens 6027, the firstmulti-aperture plate 6023 may be provided with a plurality of smallapertures on the circumference, as shown in FIG. 53B, thereby arrangingthe points projected on the x-axis so as to assume an equally spacedrelationship.

[0708] The plural primary electron beams focused are irradiated atplural points of the wafer 6028, and the secondary electron beamsemitted from the plural points irradiated are then converged by means ofattraction of the electric field of the objective lens 6027 anddeflected with the E×B separator 6026 to deliver them to the secondaryoptical system. The image formed by the secondary electron beams isfocused on a point 6036 closer to the objective lens 6027 than the point6035. This is because the secondary electron beam has energy of severaleV only, while each of the primary electron beams has energy ofapproximately 500 eV on the surface of the wafer 6028.

[0709] The secondary optical system has magnifying lenses 6029 and 6030.The secondary electron beams passed through the magnifying lenses formimages on the plural apertures of the second multi-aperture plate 6031.The secondary electron beams are detected with a plurality of detectors6032 after passage through the apertures thereof. Each of the pluralapertures of the second multi-aperture plate 6031 are arranged so as tocorrespond to each of the plural apertures of the first multi-apertureplate 6023, as shown in FIG. 53B.

[0710] Each of the detectors 6032 converts the secondary electron beamsinto an electric signal representing its intensity. The electric signalis then amplified with an amplifier 6033 and converted into an imagedata with an image processing unit 6034. To the image processing unit6034 is fed a scanning signal for deflecting the primary electron beamsfrom a deflector 6039, and the image processing unit 6034 obtains animage data for displaying an image on the surface of the wafer 6028. Theimage data obtained is then compared with the reference pattern todetect a defect of the wafer 6028. Further, a pattern for evaluation onthe wafer 6028 is transferred to a position in the vicinity of theoptical axis of the primary optical system by means of registration, anda signal for use in the evaluation of a line width is extracted by linescanning. The appropriate calibration of the signal permits ameasurement for a line width of the pattern on the wafer 6028.

[0711] Upon focusing the primary electron beams passed through theapertures of the first multi-aperture plate 6023 on the surface of thewafer 6028 and then forming an image on the second multi-aperture plate6031 for use in detecting the secondary electron beams emitted from thewafer 6028, it is preferred to take necessary measures to minimize theinfluences due to three aberrations, that is, distortion caused by theprimary optical system and the secondary optical system, curvature of animage plane, and field astigmatism.

[0712] Further, a crosstalk among the plural beams can be eliminated ifthe minimal value of the interval of the positions of irradiation withthe plural primary electron beams is arranged so as to be separatedapart by the distance longer than the aberration of the secondaryoptical system.

[0713] For the E×B separator 6020 of Embodiment 19 of the presentinvention, there may be used an electrode of a parallel plate type as apair of electrodes for the electrostatic deflector for forming anelectric field, the electrode of the parallel plate type beingconfigured such that the magnitude of the direction perpendicular to theoptical axis is set to be longer than the distance between theelectrodes. Therefore, the use of the electrode of the parallel platetype can make the range larger, in which the electric field having auniform and parallel strength around the optical axis is formed.

[0714] Further, in the E×B separators of Embodiments 19 and 20, there isused the coil of the saddle type for the electromagnetic deflector, anda calculated angle of the coil from the optical axis on one side is setto be 2π/3, so that no 3θ component is caused to be formed. Therefore,this configuration can make the range larger, in which the magneticfield having a uniform and parallel strength is formed around theoptical axis.

[0715] Moreover, the electromagnetic coil forms the magnetic field, sothat a deflecting current can be superimposed on the coil, therebyproviding a scanning function.

[0716] The E×B separator of Embodiments 19 and 20 is composed of acombination of the electrostatic deflector with the electromagneticdeflector, so that the aberration of the optical system can be obtainedby computing the aberration of the electrostatic deflector and the lenssystem, computing the aberration of the electromagnetic deflector andthe lens system separately, and totaling the computed aberrations.

[0717] A charged beam apparatus 7000 according to a twenty-secondembodiment of the present invention will now be described with referenceto FIGS. 55 and 56. In the present embodiment, a term “vacuum” means avacuum as referred to in this field of art.

[0718] In the charged beam apparatus 7000 shown in FIG. 55, a tipportion of a optical column 7001 or a charged beam irradiating section7002, which functions to irradiate a charged beam against a sample, ismounted to a housing 7014 defining a vacuum chamber C. The sample “S”loaded on a table of an XY stage 7003 movable in the X direction (thelateral direction in FIG. 55) is positioned immediately below theoptical column 7001. The XY stage 7003 of high precision allows thecharged beam to be irradiated onto this sample S accurately in anyarbitrary location of the sample surface.

[0719] A pedestal 7006 of the XY stage 7003 is fixedly mounted on abottom wall of the housing 7014, and a Y table 7005 movable in the Ydirection (the vertical direction on paper in FIG. 55) is loaded on thepedestal 7006. Convex portions are formed on both of opposite sidewallfaces (the left and the right side faces in FIG. 55) of the Y table 7005respectively, each of which projects into a concave groove formed on aside surface facing to the Y table in either of a pair of Y-directionalguides 7007 a and 7007 b mounted on the pedestal 7006. The concavegroove extends approximately along the full length of the Y directionalguide in the Y direction.

[0720] A top, a bottom and a side faces of respective convex portionsprotruding into the grooves are provided with known hydrostatic bearings7011 a, 7009 a, 7010 a, 7011 b, 7009 b and 7010 b respectively, throughwhich a high-pressure gas is blown out and thereby the Y table 7005 issupported by the Y directional guides 7007 a and 7007 b in non-contactmanner so as to be movable smoothly reciprocating in the Y direction.Further, a linear motor 7012 of known structure is arranged between thepedestal 7006 and the Y table 7005 for driving the Y table 7005 in the Ydirection. The Y table is supplied with the high-pressure gas through aflexible pipe 7022 for supplying a high-pressure gas, and thehigh-pressure gas is further supplied to the above-described hydrostaticbearings 7009 a to 7011 a and 7009 b to 7011 b though a gas passage (notshown) formed within the Y table. The high-pressure gas supplied to thehydrostatic bearings blows out into a gap of some microns to some tenmicrons formed respectively between the bearings and the opposing guideplanes of the Y directional guide so as to position the Y tableaccurately with respect to the guide planes in the X and Z directions(up and down directions in FIG. 55).

[0721] The X table 7004 is loaded on the Y table so as to be movable inthe X direction (the lateral direction in FIG. 55). A pair of Xdirectional guides 7008 a and 7008 b (only 7008 a is illustrated) withthe same configuration as of the Y directional guides 7007 a and 7007 bis arranged on the Y table 7005 with the X table 7004 sandwichedtherebetween. Concave grooves are also formed in the X directionalguides on the sides facing to the X table and convex portions are formedon the side portions of the X table (side portions facing to the Xdirectional guides). The concave groove extends approximately along thefull length of the X directional guide. A top, a bottom and a side facesof respective convex portions of the X table 7004 protruding into theconcave grooves are provided with hydrostatic bearings (not shown)similar to those hydrostatic bearings 7011 a, 7009 a, 7010 a, 7011 b,7009 b and 7010 b in the similar arrangements. A linear motor 7013 ofknown configuration is disposed between the Y table 7005 and the X table7004 so as to drive the X table in the X direction.

[0722] Further, the X table 7004 is supplied with a high-pressure gasthrough a flexible pipe 7021, and thus the high-pressure gas is suppliedto the hydrostatic bearings. The X table 7004 is supported highlyprecisely with respect to the Y directional guide in a non-contactmanner by way of said high-pressure gas blowing out from the hydrostaticbearings to the guide planes of the X-directional guides. The vacuumchamber C is evacuated through vacuum pipes 7019, 7020 a and 7020 bcoupled to a vacuum pump of known structure. Those pipes 7020 a and 7020b penetrate through the pedestal 7006 to the top surface thereof to opentheir inlet sides (inner side of the vacuum chamber) in the proximity ofthe locations to which the high-pressure gas is ejected from the XYstage 7003, so that the pressure in the vacuum chamber may be preventedto the utmost from rising up by the blown-out gas from the hydrostaticbearings.

[0723] A differential exhausting mechanism 7025 is arranged so as tosurround the tip portion of the optical column 7001 or the chargedparticles beam irradiating section 7002, so that the pressure in acharged particles beam irradiation space 7030 can be controlled to besufficiently low even if there exists high pressure in the vacuumchamber C. That is, an annular member 7026 of the differentialexhausting mechanism 7025 mounted so as to surround the charged beamirradiating section 7002 is positioned with respect to the housing 7014so that a micro gap (in a range of some microns to some-hundred microns)7040 can be formed between the lower face thereof (the surface facing tothe sample S) and the sample, and an annular groove 7027 is formed inthe lower face thereof.

[0724] That annular groove 7027 is coupled to a vacuum pump or the like,though not shown, through an exhausting pipe 7028. Accordingly, themicro gap 7040 can be exhausted through the annular groove 7027 and theexhausting pipe 7028, and if any gaseous molecules from the chamber Cattempt to enter the space 7030 circumscribed by the annular member7026, they may be exhausted. Thereby, the pressure within the chargedbeam irradiation space 7030 can be maintained to be low and thus thecharged beam can be irradiated without any troubles. That annular groovemay be made doubled or tripled, depending on the pressure in the chamberand the pressure within the charged beam irradiation space 7030.

[0725] Typically, dry nitrogen is used as the high-pressure gas to besupplied to the hydrostatic bearings. If available, however, a muchhigher-purity inert gas should be preferably used instead. This isbecause any impurities, such as water contents or oil and fat contents,included in the gas could stick on the inner surface of the housingdefining the vacuum chamber or on the surfaces of the stage componentsleading to the deterioration in vacuum level, or could stick on thesample surface leading to the deterioration in vacuum level in thecharged beam irradiation space.

[0726] It should be appreciated that though typically the sample S isnot placed directly on the X table, but may be placed on a sample tablehaving a function to detachably carry the sample and/or a function tomake a fine tuning of the position of the sample relative to the XYstage 7003, an explanation therefor is omitted in the above descriptionfor simplicity due to the reason that the presence and structure of thesample table has no concern with the principal concept of the presentinvention.

[0727] Since a stage mechanism of a hydrostatic bearing used in theatmospheric pressure can be used in the above-described charged beamapparatus 7000 mostly as it is, a high precision stage having anequivalent level of precision to those of the stage of high-precisionadapted to be used in the atmospheric pressure, which is typically usedin an exposing apparatus or the likes, may be accomplished for an XYstage to be used in a charged beam apparatus with equivalent cost andsize. It should be also appreciated that in the above description, theconfiguration and arrangement of the hydrostatic guide and the actuator(the linear motor) have been explained only as an example, and anyhydrostatic guides and actuators usable in the atmospheric pressure maybe applicable.

[0728]FIG. 56 shows an example of numeric values representative of thedimensions of the annular grooves formed in the annular member 7026 ofthe differential pumping mechanism 7025. The annular member 7026 of FIG.56 has a doubled structure of annular grooves 7027 a and 7027 b, whichare separated from each other in the radial direction and evacuated byTMP and DP respectively.

[0729] The flow rate of the high-pressure gas supplied to thehydrostatic bearing is typically in the order of about 20 L/min (in theconversion into the atmospheric pressure). Assuming that the vacuumchamber C is evacuated by a dry pump having a function of pumping speedof 20000 L/min through a vacuum pipe with an inner diameter of 50 mm anda length of 2 m, the pressure in the vacuum chamber will be about 160 Pa(about 1.2 Torr). At that time, with the applied size of the annularmember 7026, the annular groove and others of the differential pumpingmechanism as illustrated in FIG. 56, the pressure within the chargedparticles beam irradiation space 7030 can be controlled to be 10⁻⁴ Pa(10⁻⁶ Torr).

[0730]FIG. 57 shows a charged particles beam apparatus 7000 according toa twenty-third embodiment of the present invention. A vacuum chamber Cdefined by a housing 7014 is connected with a dry vacuum pump 7053 viavacuum pipes 7074 and 7075. An annular groove 7027 of a differentialpumping mechanism 7025 is connected with an ultra-high vacuum pump or aturbo molecular pump 7051 via a vacuum pipe 7070 connected to an exhaustport 7028. Further, the interior of a optical column 7001 is connectedwith a turbo molecular pump 7052 via a vacuum pipe 7071 connected to anexhaust port 7018. Those turbo molecular pumps 7051 and 7052 areconnected to the dry vacuum pump 7053 through vacuum pipes 7072 and7073.

[0731] In the charged particles beam apparatus 7000 shown in FIG. 57,the single dry vacuum pump has been used to serve both as a roughingvacuum pump of the turbo molecular pump and as a pump for vacuum pumpingof the vacuum chamber, but alternatively multiple dry vacuum pumps ofseparate systems may be employed for pumping, depending on the flow rateof the high-pressure gas supplied to the hydrostatic bearings of the XYstage, the volume and inner surface area of the vacuum chamber and theinner diameter and length of the vacuum pipes.

[0732] A high-purity inert gas (N₂ gas, Ar gas or the like) is suppliedto a hydrostatic bearing of an XY stage 7003 through flexible pipes 7021and 7022. Those gaseous molecules blown out of the hydrostatic bearingare diffused into the vacuum chamber and evacuated by the dry vacuumpump 7053 through exhaust ports 7019, 7020 a and 7020 b. Further, thosegaseous molecules having invaded into the differential pumping mechanismand/or the charged particles beam irradiation space are sucked from theannular groove 7027 or the tip portion of the optical column 7001through the exhaust ports 7028 and 7018 to be exhausted by the turbomolecular pumps 7051 and 7052, and then those gaseous molecules, afterhaving been exhausted by the turbo molecular pumps, are furtherexhausted by the dry vacuum pump 7053.

[0733] In this way, the high-purity inert gas supplied to thehydrostatic bearing is collected into the dry vacuum pump and thenexhausted away.

[0734] On the other hand, the exhaust port of the dry vacuum pump 7053is connected to a compressor 7054 via a pipe 7076, and an exhaust portof the compressor 7054 is connected to flexible pipes 7021 and 7022 viapipes 7077, 7078 and 7079 and regulators 7061 and 7062. Owing to thisconfiguration, the high-purity inert gas exhausted from the dry vacuumpump 7053 is compressed again by the compressor 7054 and then the gas,after being regulated to an appropriate pressure by regulators 7061 and7062, is supplied again to the hydrostatic bearings of the XY stage.

[0735] In this regard, since the gas to be supplied to the hydrostaticbearings is required to be as highly purified as possible in order notto have any water contents or oil and fat contents included therein, asdescribed above, the turbo molecular pump, the dry pump and thecompressor are all required to have such structures that prevent anywater contents or oil and fat contents from entering the gas flow path.It is also considered effective that a cold trap, a filter 7060 or thelike is provided in the course of the outlet side piping 7077 of thecompressor so as to trap the impurities such as water contents or oiland fat contents, if any, included in the circulating gas and to preventthem from being supplied to the hydrostatic bearings.

[0736] This may allow the high purity inert gas to be circulated andreused, and thus allows the high-purity inert gas to be saved, while theinert gas would not remain desorbed into a room where the presentapparatus is installed, thereby eliminating a fear that any accidentssuch as suffocation or the like would be caused by the inert gas.

[0737] A circulation piping system is connected with a high-purity inertgas supply source 7063, which serves both to fill up with thehigh-purity inert gas all of the circulation systems including thevacuum chamber C, the vacuum pipes 7070 to 7075, and the pipes incompression side 7076 to 7080, prior to the starting of the gascirculation, and to supply a deficiency of gas if the flow rate of thecirculation gas decreases by some reason. Further, if the dry vacuumpump 7053 is further provided with a function for compressing up to theatmospheric pressure or more, it may be employed as a single pump so asto serve both as the dry vacuum pump 7053 and the compressor 7054. Asthe ultra-high vacuum pump to be used for evacuating the optical column,other pumps including an ion pump and a getter pump may be used insteadof the turbo molecular pump. Further, instead of the dry vacuum pump, adry pump of other type, for example, a dry pump of diaphragm type may beused.

[0738]FIG. 58 shows a charged particles beam apparatus 7100 according tothe twenty-third embodiment of the present invention. The charged beamapparatus 7100 includes an optical system 7160 and a detector 7180, eachapplicable to the charged particles beam apparatus 7000 of FIG. 57. Theoptical system 7160 comprises a primary optical system 7161 forirradiating the charged particles beam against the sample S loaded onthe stage 7003 and a secondary optical system 7171 into which thesecondary electrons emanated from the sample are to be introduced.

[0739] The primary optical system 7161 comprises an electron gun 7162for emitting the charged particles beam, a lens systems composed of twostages of electrostatic lenses 7163 and 7164 for converging the chargedparticles beam emitted from the electron gun 7162, a deflector 7165, aWien filter or an E×B separator 7166 for deflecting the charged beam soas for an optical axis thereof to be directed to perpendicular to asurface of an object, and a lens system composed of two stages ofelectrostatic lenses 7167 and 7168, wherein those components describedabove are arranged in the order with the electron gun 7162 at thetopmost location so that the optical axis of the charged beam isinclined to the line normal to a surface of the sample S (a samplesurface) as illustrated in FIG. 58. The E×B separating system 7166comprises an electrode 7661 and a magnet 7662.

[0740] The secondary optical system 7171 is another optical system towhich the secondary electrons emanated from the sample S are introduced,which comprises a lens system composed of two stages of electrostaticlenses 7172 and 7173 disposed in an upper side of the E×B typeseparating system of the primary optical system. The detector 7180detects the secondary electrons sent through the secondary opticalsystem 7171. Since the structures and functions of respective componentsof said optical systems 7160 and said detector 7180 are similar to thosein the prior art, a detailed description thereof should be omitted.

[0741] The charged particles beam emitted from the electron gun 7162 isappropriately shaped in a square aperture of the electron gun,contracted by the lens system of two stages of lenses 7163 and 7164, andthen, after the optical axis thereof being adjusted by the deflector7165, the charged beam is formed into an image of 1.25 mms square on adeflection principal plane of the E×B separating system 7166. The E×Bseparating system 7166 is designed such that an electric field and amagnetic field are crossed at a right angle within a plane orthogonal toa normal line of the sample, wherein when the relationship among theelectric field, the magnetic field and the energy of electrons satisfiesa certain condition, the electrons are advanced straight forward, andfor the case other than the above, the electrons are deflected into apredetermined direction depending on said mutual relationship among theelectric field, the magnetic field and the energy of electrons.

[0742] The relationship has been set such that the charged beam from theelectron gun is deflected to enter the sample S at a right angle and thesecondary electrons emanated from the sample can be advanced straightahead toward the detector 7180. The shaped beam, after having beendeflected by the E×B deflecting system, is contracted to ⅕ in size withthe lens system composed of the lenses 7167 and 7168 to be projectedonto the sample S.

[0743] The secondary electrons emanated from the sample S, which havethe information of a pattern image, are magnified by the lens systemscomposed of the lenses 7167 and 7168 and the lenses 7172 and 7173 so asto form the secondary electron image on the detector 7180. These fourstages of magnifying lenses, which are composed of the lens system ofthe lenses 7167 and 7168 forming a symmetrical tablet lens and the lenssystem of the lenses 7172 and 7173 also forming another symmetricaltablet lens, make up the lenses of no distortion.

[0744] The charged particles beam apparatus 7000 shown in FIGS. 55 to 58may be applied to the semiconductor device manufacturing method shown inFIGS. 12 and 13. That is, using the charged beam apparatus 7000 in thewafer inspection process of FIG. 12 or the exposing process of FIG. 13allows the finer pattern to be inspected or exposed with high precisionand certain stableness, which allows to improve the yield of theproducts and to prevent the defective product from being delivered.

[0745] The charged particles beam apparatus 7000 shown in FIGS. 55 to 58provides such effects as below:

[0746] (A) A processing by the charged beam can be stably applied to asample on the stage by use of the stage having a structure similar tothat of a stage of hydrostatic bearing type which is typically used inthe atmospheric pressure (a stage supported by the hydrostatic bearinghaving no differential exhausting mechanism);

[0747] (B) An affection on the vacuum level in the charged particlesbeam irradiation region can be minimized, and thereby the processing bythe charged particles beam applied to the sample can be stabilized;

[0748] (C) An inspection apparatus which accomplishes the positioningperformance of the stage with high precision and provides a stablevacuum level in the irradiation region of the charged particles beam canbe provided in low cost;

[0749] (D) An exposing apparatus which accomplishes the positioningperformance of the stage with high precision and provides a stablevacuum level in the irradiation region of the charged particles beam canbe provided in low cost; and

[0750] (E) A fine semiconductor circuit can be formed by manufacturingthe semiconductor using an apparatus which accomplishes the positioningperformance of the stage with high precision and provides a stablevacuum level in the irradiation region of the charged particles beam.

[0751]FIG. 59 is a schematic diagram illustrating an electron beamapparatus 8000 according to a twenty-fifth embodiment of the presentinvention, wherein an electron beam emitted from an electron gun 8001 isfocused by a condenser lens 8002 to form a cross-over at a point 8004.

[0752] A first multi-aperture plate 8003 having a plurality of apertures8003′ is disposed beneath the condenser lens 8002, and thereby aplurality of primary electron beams is formed. Each of the plurality ofprimary electron beams formed by the first multi-aperture plate, afterhaving been contracted by a demagnification lens 8005 to be focused ontoa point 8015, is focused by an objective lens 8007 onto a sample 8008.The plurality of primary electron beams emitted through the firstmulti-aperture plate 8003 is deflected by a deflector disposed betweenthe reduction lens 8005 and the objective lens 8007 so as tosimultaneously scan different locations on a surface of the sample 8008.

[0753] In order to eliminate an effect of field curvature aberrationpossibly caused by the reduction lens 8005 and the objective lens 8007,the multi-aperture plate 8003 is provided with a plurality of apertures8003′ arranged along a circle on said multi-aperture plate 8003 suchthat projected points of centers of said apertures 8003′ onto x-axis maybe equally spaced, as shown in FIG. 60.

[0754] In the electron beam apparatus 8000 of the twenty-fifthembodiment shown in FIG. 59, from a plurality of spots on the sample8008 irradiated by the plurality of primary electron beams, a pluralityof secondary electron beams is emanated, attracted by an electric fieldof the objective lens 8007 to be focused narrower, deflected by an E×Bseparator 8006, and then introduced into a secondary optical system. Asecondary electron image is focused on a point 8016 which is closer tothe objective lens 8007 than the point 8015. This is because thesecondary electron beam has only a few eV of energy while each of theprimary electron beams has 500 eV of energy on the sample surface.

[0755] The secondary optical system includes magnifying lenses 8009 and8010, and the secondary electron beam, after having passed through thesemagnifying lenses 8009 and 8010, passes through a plurality of aperturesformed on a second multi-aperture plate 8011, and is focused on aplurality of electron detectors 8012. It is to be noted that each of theplurality of apertures formed on the second multi-aperture plate 8011disposed in front of the detectors 8012 corresponds to each of theplurality of apertures 8003′ formed on the first multi-aperture plate8003 in a geometric relationship therebetween in a manner of one-by-onebasis.

[0756] Each of the detectors 8012 converts a detected secondary electronbeam into an electric signal representative of intensity thereof. Theelectric signal output from each of the detectors, after having beenamplified respectively by an amplifier 8013, is received by an imageprocessing section 8014 to be converted into an image data. Since theimage processing section 8014 is further supplied with a scanning signalfor deflecting the primary electron beam, the image processing section8014 can display an image representative of the surface of the sample8008.

[0757] Comparing this image with a reference pattern allows any defectsof the sample 8008 to be detected, and also a line width of a pattern onthe sample 8008 can be measured in such a way that the pattern to bemeasured of the sample 8008 is moved by a registration to a proximity ofan optical axis of the primary optical system, and the pattern isline-scanned to extract a line width evaluation signal, which is in turnappropriately calibrated.

[0758] In this regard, when the primary electron beams passed throughthe apertures of the first multi-aperture plate 8003 are focused on thesurface of the sample 8008, and the secondary electron beams emanatedfrom the sample are formed into an image on the detectors 8012, muchattention should be paid in order to minimize the affection by the threeaberrations, i.e., a distortion caused by the primary optical system, afield curvature and a astigmatism field.

[0759] As for a relation between the spacing among the plurality ofprimary electron beams and the secondary optical system, if the spacebetween respective primary electron beams is determined to be greaterthan the aberration of the secondary optical system, then the crosstalkamong a plurality of beams can be eliminated.

[0760] Although in the above-described optical system, the electron beamemitted from the single electron gun is passed through themulti-apertures to be formed into multi-beams, a plurality of electronguns may be provided or a single electron gun having a plurality ofemission areas of cathode may be employed.

[0761]FIG. 61 shows a simulation model for the objective lens 8007 ofFIG. 59. Reference numeral 8021 is an optical axis, 8022 is an upperelectrode of the objective lens 8007, which is set to 0 volt, 8023 is acenter electrode of the objective lens, to which high voltage is to beapplied, 8024 is an under electrode of the objective lens, which is setto earth voltage, and a sample surface 8025 is set to 4000 volts.Reference numerals 8026, 8027 and 8028 are insulator spacers forsupporting the electrodes. An image of the multi-beam in a position ofz=0 mm was focused on the sample surface 8025 by varying a position ofthe crossover produced by the demagnification lens 8005 and also byvarying the voltage of center electrode in the objective lens, and theaberration generated thereby was calculated.

[0762]FIG. 62 is a graph illustrating a result of the above simulation.In FIG. 62, the values of aberration (nm, yaxis) are shown as a functionof varied cross-over positions (mm, x-axis). An upper surface of thecenter electrode 8023 (FIG. 61) was located at z=144 mm. An r positionof the multi-beam and a half angular aperture were set to 50 μm and 5mrad respectively.

[0763] In the graph of FIG. 62, a curve 8031 indicates acoma-aberration, 8032 a magnification chromatic aberration, 8033 anastigmatism, 8034 an on-axis chromatic aberration, 8035 an fieldcurvature, 8036 a distortion, and 8037 indicates a blur.

[0764] When the multi-beams are arranged along a circle centering aroundthe optical axis, the blur 8037 is determined substantially by themagnification chromatic aberration 8032 and the on-axis chromaticaberration 8034 since the field curvature is zero. Hereupon, the energyspread of the electron beam is set to 5 eV. When the cross-over positionis set to 140 mm, the magnification chromatic aberration is reduced toalmost non-problematic level. That is, according to this simulation, itis found that the cross-over position produced by the front stage lensshould be formed in the electron gun side of the position of the centerelectrode of the objective lens (144 mm).

[0765] The electron beam apparatus 8000 of the twenty-fifth embodimentshown in FIG. 59 can be used for evaluating the wafer in thesemiconductor device manufacturing process shown in FIGS. 12 and 13.Using the electron beam apparatus of FIGS. 59 to 62 in the waferinspection process of FIG. 12 allows even the semiconductor device withfiner pattern to be inspected with high throughput, which allows ahundred percent inspection and an improvement in yield of the products,and also allows to prevent the defective product from being delivered.The electron beam apparatus 8000 of the twenty-fifth embodiment shown inFIG. 59 provides such operational effects as below:

[0766] (1) Using the multi-beams allows an evaluation of the wafer orthe like by the electron beam to be performed with high throughput; and

[0767] (2) The magnification chromatic aberration which is problematicwhen large radius is employed for arranging the multi-beams can bereduced down to non-problematic level.

[0768]FIG. 64 is a horizontal cross sectional view illustrating adetailed structure of the electron beam deflector 90 applicable to theelectron beam apparatus according to the present invention. FIG. 65 is aside elevational view taken along a line A-A of FIG. 64. As shown inFIG. 64, the electron beam deflector 90 has a configuration in which anelectric field and a magnetic field are crossed at a right angle withina plane orthogonal to an optical axis of a image projecting opticalsection, that is, an E×B configuration. Hereupon, the electric field Eis generated by a pair of electrodes 90 a and 90 b each having concavedcurved surface. The electric field generated by the electrodes 90 a and90 b are controlled by control sections 93 a and 93 b respectively. Onthe other hand, a pair of electromagnetic coils 91 a and 91 b isarranged so as to cross at a right angle with the electrodes 90 a and 90b for generating the electric field, to generate the magnetic field. Theelectrodes 90 a and 90 b for generating the electric field is designedto be point-symmetry (concentric circle type).

[0769] To improve a uniformity level of the magnetic field, a magneticpath is formed by providing a pole piece of plane parallel plate shape.A behavior of the electron beam in a longitudinal cross-section along aline A-A is shown in FIG. 65. Irradiated electron beams 91 a and 91 b,after having been deflected by the electric field generated by theelectrodes 90 a and 90 b and the magnetic field generated by theelectromagnetic coils 91 a and 91 b, enter the sample surface at a rightangle.

[0770] Incident location and angle of the electron beams 91 a and 91 bto the electron beam deflecting section 90 are univocally defined whenthe energy of the electron is given. The secondary electrons advancestraight ahead through the electron beam deflecting section 27 to enterthe image projecting optical section when respective control section 93a and 93 b, and 94 a and 94 b control the electric field generated bythe electrodes 90 a and 90 b, and the magnetic field generated by theelectromagnetic coil 91 a and 91 b such that the condition of theelectric and the magnetic fields for allowing the secondary electrons toadvance straight forward, that is, evB=eE, may be satisfied. Where, v isa velocity of electron (m/s), B is a magnetic field (T), e is a chargeamount (C), and E is the electric field (V/m).

[0771]FIG. 66 is a plan view for explaining an irradiating method of theprimary electron beam according to the present invention. In FIG. 66,the primary electron beam 100 is composed of four electron beams 101,102, 103 and 104. Each of the electron beams scan the width of 50 μm.For example, the primary electron beam 101 is initially in the left end,then scan a substrate W (sample) with a pattern 107 to the right end,and after having reached to the right end, immediately returns to theleft end, and then scans again in the right direction. Moving directionof the stage on which the substrate W is loaded is perpendicular to thescanning direction of the primary electron beam.

1. An inspection apparatus (70, 700) for inspecting an object of inspection by irradiating the object of inspection with either one of charged particles or an electromagnetic wave, comprising: a working chamber controllable into a vacuum atmosphere for inspecting an object of inspection; a beam generating means for emitting either one of the charged particles or the electromagnetic wave as a beam; an electronic optical system wherein a plurality of beams is guided to irradiate the object of inspection held in the working chamber, and secondary charged particles generated from the object are detected and led to an image processing system which forms an image based on the secondary charged particles; a data processing system for displaying and/or memorizing a state information of the object based on output of the image processing system; and a stage system for holding the object so as to be movable relative to the beam.
 2. The inspection apparatus of claim 1 comprising a transfer mechanism for holding the object and for transferring the object into or out of the working chamber.
 3. The inspection apparatus of claim 2, wherein the transfer mechanism comprises the working chamber containing the stage system and being capable to be controlled in the vacuum atmosphere, and a loader for supplying an object of inspection on the stage system in the working chamber, and wherein the working chamber is supported on a floor via a vibration isolator for isolating vibrations from the floor.
 4. The inspection apparatus of claim 1 further comprising a voltage applying system for applying voltage to the object of inspection in the working chamber; and an alignment control device for controlling alignment by observing a surface of the object of inspection in order to position the object relative to the electronic optical system.
 5. The inspection apparatus of claim 1, wherein the electronic optical system comprises an objective lens and an E×B separator, forms a plurality of beams to irradiate the object, and includes an optical system for accelerating secondary charged particles emitted by irradiation of the beams through the objective lens, separating the particles by the E×B separator, and projecting an image of secondary charged particles, and a plurality of detectors for detecting the image of secondary charged particles.
 6. The inspection apparatus of claim 3, wherein the loader comprises a first loading chamber and a second loading chamber, each being separate from the other and arranged so as to control atmosphere of its inside; a first transferring unit for transferring the object of inspection between the inside of the first loading chamber and the outside thereof; and a second transferring unit disposed at the second loading chamber for transferring the object of inspection between the inside of the first loading chamber and the stage system; wherein the inspection apparatus is further provided with a mini-environment space partitioned for feeding the object of inspection to the loader.
 7. The inspection apparatus of claim 1, further comprising a laser interferometer for detecting coordinates of the object of inspection on the stage system; wherein the coordinates of the object of inspection are determined by utilizing a pattern present on the object of inspection with the alignment control unit.
 8. The inspection apparatus of claim 6, wherein the alignment of the object of inspection includes rough alignment to be performed within the mini-environment space and alignment in the XY-directions and in the direction of rotation to be performed on the stage system.
 9. A method for manufacturing devices comprising the step of detecting a defect on a wafer during a manufacturing process or after manufacturing process using the inspection apparatus of any one of claims 1 to
 8. 10. An inspection apparatus (1000) for irradiating charged particles to a sample and for detecting secondary charged particles emitted from the sample, comprising: at least one primary optical system for irradiating the sample with a plurality of charged particle beams; and at least one secondary optical system for leading the secondary charged particles to at least one detector; wherein the plurality of the charged particle beams are irradiated each at a position separated by distance resolution of the secondary optical system.
 11. The inspection apparatus of claim 10, wherein the primary optical system has a function of scanning the charged particle beams at a distance greater than the interval of irradiation of the charged particle beams.
 12. The inspection apparatus of claim 10, wherein an electric field for accelerating the charged particle beam is applied between a first stage lens of the secondary optical system and a surface of the sample, and the secondary charged particle emitted from the surface of the sample at an angle smaller than at least 45 degree passes through the secondary optical system.
 13. The inspection apparatus of claim 10, wherein: the plurality of the charged particle beams are delivered generally perpendicularly to the surface of the sample; and the secondary charged particles are deflected with the E×B separator and separated from the primary optical system.
 14. A method for manufacturing devices comprising the step of detecting a defect on a device using the inspection apparatus of any one of claims 10 to
 13. 15. An inspection apparatus (2000) wherein a sample is placed on an XY-stage so as to be moved to an optional position in a vacuum atmosphere, and a charged particle beam is irradiated on a surface of the sample, and wherein the XY-stage has a non-contact supporting mechanism with a hydrostatic bearing and a vacuum sealing mechanism by differential exhausting, a conductance reducing partition is disposed between a location where the surface of the sample is irradiated by the charged beam and a hydrostatic bearing supporting portion of the XY-stage, and a pressure difference is generated between a region of irradiation of the charged particle beam and the hydrostatic bearing supporting portion.
 16. The inspection apparatus of claim 15, wherein the partition contains a differential exhaust structure.
 17. The inspection apparatus of claim 15, wherein the partition is provided with a cold trap function.
 18. The inspection apparatus of claim 15, wherein the partition is disposed at two locations, one being in the vicinity of the position of irradiation of the charged particle beam, and the other being in the vicinity of the hydrostatic bearing.
 19. The inspection apparatus of claim 15, wherein a gas to be fed to the hydrostatic bearing of the XY-stage is nitrogen or an inert gas.
 20. The inspection apparatus of claim 15, wherein a surface of the XY-stage facing at least the hydrostatic bearing is subjected to surface processing to reduce a gas to be emitted.
 21. An inspection apparatus for inspecting a defect on the surface of a semiconductor wafer by using the inspection apparatus of claim
 15. 22. An exposure apparatus for delineating a circuit pattern of a semiconductor device on a surface of the semiconductor wafer or a reticle substrate by using the inspection apparatus of any one of claims 15 to
 20. 23. A manufacturing method for manufacturing a semiconductor by using the inspection apparatus of any one of claims 15 to
 20. 24. A inspection apparatus (3000) for inspecting a defect of a sample, comprising: an image acquisition means for acquiring an image of a plurality of inspection regions that are displaced from each other while partially overlapping with each other on the surface of the sample; a memory means for storing a reference image; and a defect deciding means for determining a defect of the sample by comparing an image of each of the plurality of the inspection regions acquired by the image acquisition means with the reference image stored in the memory means.
 25. The inspection apparatus of claim 24, further comprising an electronic optical system (3100) for discharging a secondary charged particle beam from the sample by irradiating each of the plurality of the inspection regions with the primary charged particle beam; wherein the image acquisition means is adapted to acquire an image of each of the plurality of the inspection regions one after another by detecting the secondary charged particle beams emitted from the plurality of the inspecting regions.
 26. The inspection apparatus of claim 25, wherein the electronic optical system (3100) is provided with a source of particles for discharging primary charged particles and a deflecting means for deflecting the primary charged particles; and the plurality of the inspection regions are irradiated one after another with the primary charged particles emitted from the source of the particles by deflecting the primary charged particle with the deflecting means.
 27. The inspection apparatus of any one of claims 24 to 26, further comprising: a primary optical system for irradiating the sample with a primary charged particle beam; and a secondary optical system for guiding the secondary charged particles to a detector.
 28. A method for inspecting a defect on a wafer during a processing or as a finished product using the inspection apparatus of any one of claims 24 to
 26. 29. An inspection apparatus (4000) comprising: a primary electronic optical system for irradiating a surface of a sample by a plurality of primary charged particles; and a secondary electronic optical system for leading a secondary charged particles emitted from each point of irradiation by the plurality of the primary charged particles formed on the surface of the sample to a secondary electron detector after separation from the primary electronic optical system by accelerating the secondary charged particles by means of an electric field applied between an objective lens and the surface of the sample, converging the secondary charged particles accelerated, and separating the secondary charged particles from the primary optical system by an E×B separator disposed between the objective lens and a lens of the objective lens at the side of a beam generating means; wherein the primary electronic optical system is configured in such a manner that points of irradiation by the primary charged particles are formed on the surface of the sample in a two-dimensional way, and that points of the irradiation points projected in one-axial direction are located at equal intervals.
 30. The inspection apparatus of claim 29, wherein the plurality of the primary charged particle beams are arranged so as to minimize a maximum value of a distance between optional two points out of the points of irradiation formed two-dimensionally on the surface of the sample.
 31. An inspection apparatus (4000) having a primary charged particle beam irradiation device for irradiating a surface of a sample with a plurality of charged particle beams; and a secondary charged particle detector for detecting secondary charged particles respectively from points of irradiation by the plurality of the primary charged particle beams formed on the surface of the sample, wherein the secondary charged particles from a predetermined region on the surface of the sample are detected while transferring the sample; wherein the primary charged particle beam irradiation device is arranged in such a manner that the points of irradiation by the primary charged beams to be formed on the surface of the sample are disposed in rows N in a direction of transferring the sample and in columns M in a direction perpendicular to the direction of transferring the sample.
 32. The inspection apparatus of claim 31, wherein the primary charged particle beam irradiation device comprises a beam generating means, an aperture plate having a plurality of apertures adapted to form a plurality of charged particle beams, the beams being formed by containing particles generated by the beam generating means to form irradiation points disposed in rows N in a direction of transferring the sample and in columns M in a direction perpendicular to the direction of transferring the sample, and the apertures are located within a range of a predetermined electron density of the charged particles emitted from the beam generating means.
 33. The inspection apparatus of claim 32, wherein each of the points of irradiation by the primary charged particle beams is scanned by; (a distance between the columns)/(number N of the rows) +α in a direction perpendicular to the direction of transferring the sample, where a is a minimal distance.
 34. The inspection apparatus of any one of claims 29 to 33, wherein a secondary electron beam detected by a secondary electron beam detector is used for performing a measurement including measuring a defect of the sample surface, measuring a line width of an integrated circuit formed on the surface of the sample, and measuring a voltage contrast or measuring precision of alignment.
 35. The inspection apparatus of claim 32 or 33, wherein the primary charged particle beam irradiation device is provided with a beam generating means and a plurality of primary charged particle beam irradiation systems, each primary charged particle beam irradiation system being adapted to form a plurality of points of irradiation with primary electron beams on the surface of the sample and the aperture plate and to prevent the primary electron beam of each primary electron beam irradiation system from interfering with the primary electron beam of the other primary electron beam irradiation system; and wherein a plurality of the secondary electron detectors are disposed so as to correspond to each of the primary electron beam irradiation systems.
 36. An inspection apparatus (4100) comprising: a primary optical system having a single beam generating means for irradiating output beam to an aperture plate with a plurality of apertures and for irradiating charged particles passed through the plurality of apertures on a sample, wherein the secondary charged particles generated from the sample are separated from the primary optical system by an E×B separator, and the separated secondary charged particles are delivered into a plurality of detectors so as to be detected through a secondary optical system having at least one stage lens.
 37. An inspection apparatus (4100) comprising: a primary optical system having a beam generating means with an integrated cathode for irradiating output beam to an aperture plate with a plurality of apertures and for focusing and irradiating beams passed through the plurality of apertures on a sample surface, wherein the secondary charged particles generated from the sample are separated from the primary optical system by an E×B separator, and the separated secondary charged particles are delivered into a plurality of detectors so as to be detected through a secondary optical system having at least one stage lens.
 38. An inspection apparatus (4100) for irradiating a beam emitted from a beam generating means to an aperture plate having a plurality of apertures to produce images of the plurality of the apertures, delivering the plurality of the images to a sample, separating the secondary charged particles generated from the sample from a primary optical system to deliver the secondary charged particles into a secondary optical system, and enlarging the secondary charged particles by the secondary optical system to project to a surface of a detector wherein a single aperture plate is disposed in a position deviated toward the side of the source of the electron beam from the position of an image of the beam generating means formed by a lens of the primary optical system, and the position of the single aperture plate in the direction of the optical axis thereof is disposed so as to minimize the difference in beam strength of the beams to be delivered from each aperture to the surface of the sample.
 39. An inspection apparatus (4100) for irradiating a beam emitted from a beam generating means to an aperture plate having a plurality of apertures to produce images of the plurality of the apertures, delivering the plurality of the images to a sample, separating the secondary charged particles generated from the sample from a primary optical system to deliver the secondary charged particles into a secondary optical system, and enlarging the secondary charged particles by the secondary optical system to project to a surface of a detector, wherein a single aperture plate is disposed in a position deviated toward the side of the beam generating means from a position of an image of the beam generating means formed by the primary optical system, and wherein an amount of deviation is set so that an amount of detection of the secondary charged particles obtained when a sample with no pattern is disposed on the surface of the sample minimizes a difference thereof between the plurality of the apertures.
 40. A manufacturing method for manufacturing a device wherein a wafer on the way of a manufacturing process is evaluated by using the inspection apparatus of any one of claims 36 to
 39. 41. An inspection apparatus (4200) for irradiating a beam emitted from a beam generating means to an aperture plate having a plurality of apertures, projecting and scanning a reduced image of the primary charged particles passed through the plurality of the apertures by using a primary optical system on a sample, and enlarging the secondary charged particles emitted from the sample by a secondary optical system to project them into a detector, wherein the positions of the plurality of the apertures are disposed so as to correct a distortion of the primary optical system.
 42. An inspection apparatus (4200) for irradiating a first multi-aperture plate having a plurality of apertures with beams emitted from one or more beam generating means, projecting and scanning a reduced image of the primary charged particle beams passed through the plurality of the apertures on a sample by using a primary optical system, and enlarging by a secondary optical system the secondary charged particles emitted from the sample to detect them using a detector having a plurality of detecting elements, and including a second multi-aperture plate with a plurality of apertures disposed in front of the detector; wherein the positions of the apertures formed in the second multi-aperture plate are arranged so as to correct a distortion in the secondary optical system.
 43. An inspection apparatus (4200) for irradiating a beam emitted from a beam generating means to an aperture plate having a plurality of apertures, projecting and scanning a reduced image of primary charged particles passed through the plurality of the apertures on a sample by using a primary optical system, and projecting images of secondary charged particles emitted from the sample by a secondary optical system to a detector, wherein shapes of the plurality of the apertures are set so as to correct field astigmatism of the primary optical system.
 44. An inspection apparatus (4200) adapted to acquire image data in a multi-channel by irradiating an aperture plate having a plurality of apertures with beams emitted from beam generating means, projecting and scanning reduced images of charged particles passed through the apertures thereof on the sample with a primary optical system including an E×B separator, and projecting images of the secondary charged particles emitted from the sample on a detector by means of an imaging optical system; wherein the images of the secondary charged particles are formed on a deflecting main plane of the E×B separator at the sample side, and images of the primary charged particles from the plurality of the apertures are formed on the deflecting main plane of the E×B separator.
 45. A method for manufacturing devices wherein a wafer in the process of being manufactured is evaluated by using the inspection apparatus of any one of claims 41 to
 44. 46. An inspection apparatus (4300) having a primary optical system containing a beam generating means for discharging charged particles, an aperture plate with a plurality of apertures, a plurality of lenses, and at least two E×B separators disposed in a spaced relationship with each other, the primary optical system being adapted to irradiate the surface of a sample to be inspected by the beam emitted from the beam generating means, and a secondary optical system for separating secondary charged particles emitted from the sample from the primary optical system by one of the at least two E×B separators, and delivering and detecting the secondary charged particles in secondary charged particle detectors; wherein an image of each of the plurality of the apertures is formed by irradiating the aperture plate with the charged particles emitted from the beam generating means, a position of the image of each of the plurality of the apertures thereof is aligned with a position of each of the E×B separators, and directions of the charged particles deflected by electric fields of the E×B separators are arranged to be inverse from each other, when looked from on the sample surface.
 47. The inspection apparatus of claim 46, wherein the primary optical system and the secondary optical system are disposed in two rows and in plural columns so as to prevent a path of secondary charged particles deflected by one of the E×B separators from interfering with a path of the secondary charged particles deflected by the other E×B separator.
 48. An inspection apparatus (4300) having a primary optical system containing a beam generating means discharging a beam, an aperture plate with a plurality of apertures, a plurality of lenses, and an E×B separator so as to irradiate a surface of a sample to be inspected with the beam emitted from the beam generating means, and a secondary optical system for separating secondary charged particles emitted from the sample from the primary optical system by the E×B separator, and delivering and detecting the secondary charged particles in a secondary charged particle detector; wherein an image of each of the plurality of the apertures is formed by irradiating the aperture plate with the beam from the beam generating means, and a scanning voltage is superimposed on an electric field of the E×B separator so as to have the beam deflect.
 49. The inspection apparatus of claim 46 or 48, wherein the primary optical system and the secondary optical system are disposed in two rows and in plural columns so that paths of the secondary charged particles deflected by the E×B separator do not interfere with each other.
 50. A method for manufacturing devices wherein a wafer during a manufacturing process is evaluated by using the inspection apparatus of claim
 49. 51. An inspection apparatus (4400) adapted to irradiate a sample with a primary charged articles by a primary optical system, delivering secondary charged particles emitted from the sample by an E×B separator after the particles pass through an objective lens into a secondary optical system, thereafter increasing a distance between secondary charged particle beams by at least one stage of lens, and detecting the secondary charged particle beams by a plurality of detectors, wherein at least three different energizing voltages are separately supplied to the objective lens so as to detect at least three data which represent rising widths of electric signals corresponding to strength of the secondary charged particles and which are obtained when a pattern edge parallel with a first direction is scanned in a second direction.
 52. The inspection apparatus (4400) comprising a plurality of optical column opposite to a sample, wherein the optical column includes the inspection apparatus of claim 51, and a primary optical system of each of the optical column irradiates the sample with primary charged particles at a position of the sample which is different from that using the other lens barrel.
 53. The inspection apparatus of claim 52 or 53 wherein the apparatus is constructed so that an energizing condition of an objective lens is obtained under a state where a pattern on a wafer is electrically charged.
 54. An inspection apparatus (4400) adapted to irradiate a sample with a primary charged particles by a primary optical system, delivering secondary charged particles emitted from the sample by an E×B separator after the particles pass an objective lens into a secondary optical system, thereafter increasing a distance between secondary charged particle beams by at least one stage of lens, and detecting the secondary charged particle beams by a plurality of detectors, wherein the objective lens comprises a first electrode to which a first voltage adjacent to an earth is applied and a second electrode to which a second voltage higher than the first voltage is applied, wherein a focal length of the objective lens is varied by changing the first voltage applied to the first electrode, and an energizing means for energizing the objective lens comprises means for changing the voltage applied to the second electrode for changing significantly the focal length of the objective lens, and means for changing the voltage applied to the first electrode for changing the focal length in a short time.
 55. A method for manufacturing semiconductor devices wherein a wafer during a manufacturing process or after processing is evaluated by using the inspection apparatus of any one of claims 51-54.
 56. An inspection apparatus (4500) having a primary optical system and a secondary optical system, the primary optical system being arranged to convert a beam emitted from a single beam generating means into multi-beams by an aperture plate having a plurality of apertures, to reduce the multi-beams by an electrostatic lens of at least two stages, and to scan a sample to be inspected, and the secondary optical system being arranged to separate the secondary charged particle beams emitted from the sample from the first optical system by an E×B separator after passage through an electrostatic objective lens, to enlarge the secondary charged particle beams by an electrostatic lens of at least one stage, and to deliver the secondary charged particle beams to each of a plurality of detection devices; wherein the sample is evaluated by at least two kinds of pixel dimensions so as to enable the sample to be evaluated in a mode in which throughput is high yet resolution is relatively low and in a mode in which throughput is small yet resolution is high.
 57. The inspection apparatus of claim 56, wherein a rate of reduction of the multi-beams in the primary optical system is associated with a rate of magnification in the electrostatic lens of the secondary optical system.
 58. The inspection apparatus of claim 56, wherein a crossover image by the primary optical system is formed on a principal plane of an objective lens in the mode in which the throughput is high yet resolution is relatively low.
 59. The inspection apparatus of claim 56, wherein the rate of magnification of the secondary optical system is adjusted by the electrostatic lens disposed at the detector side than an aperture aperture disposed in the secondary optical system.
 60. A method for manufacturing devices, wherein a wafer being processed is evaluated by using the inspection apparatus of any one of claims 56 to
 59. 61. An inspection apparatus (5000) comprising a primary optical system for generating primary charged particles, forcusing them, and irradiating a sample by scanning with the primary charged particles, a secondary optical system for receiving secondary charged particles emitted from portions of the sample where the primary charged particles are irradiated, and the secondary optical system having a lens of at least one stage and a detector for detecting the secondary primary charged particles, wherein the secondary charged particles emitted from the portions of the sample where the primary charged particles are irradiated are accelerated and are separated from the primary optical system by an E×B separator, and enter the secondary optical system, and an image the secondary charged particles is magnified by the lens and detected by a detector, wherein the primary optical system generates a plurality of the primary charged particles and irradiates the sample concurrently therewith, and a plurality of the detectors is disposed so as to correspond to the number of the primary charged particles beams, a retarding voltage applying unit is disposed to apply a retarding voltage to the sample, and a charging investigating function for investigating a charging status of the sample is provided.
 62. The inspection apparatus of claim 61, further comprising a function for determining an optimal retarding voltage on the basis of information relating to a charged-up state from the charging investigating function, and a function for applying the voltage to the sample or varying irradiation amount of the primary charged particles.
 63. An inspection apparatus (5000) comprising an optical system for irradiating a sample with a plurality of charged particles and a charging investigating function, wherein the charging investigating function evaluates a distortion of a pattern or a fading of a pattern at a particular portion of the sample when secondary charged particles generated by irradiating the sample with primary electron beams are detected with a plurality of detectors to form an image, and evaluates in such a way that a charging is large when the distortion of the pattern or the fading thereof is determined to be large.
 64. The inspection apparatus of any one of claims 61 to 63, wherein the charging investigating function is arranged so that it is capable of applying a retarding voltage having a variable value to a sample, an image of a pattern in the vicinity of a boundary where a pattern density of the sample varies to a great extent is formed under a state where at least two retarding voltages are applied, and a display displays the image to enable an operator to evaluate a distortion of the pattern or a fading of the pattern is provided.
 65. A method for manufacturing a device wherein a wafer during a process or after a process is evaluated by using the inspection apparatus of claim
 64. 66. An E×B separator (6020) for forming an electric field and a magnetic field intersecting an optical axis at right angles and separating at least two charged particles having different travelling directions, comprising: an electrostatic deflector having a pair of electrodes of a parallel flat plates for forming an electric field, an interval between the electrodes with each other being set so as to be shorter than a length of the electrode intersecting the electric field at right angles; and an electromagnetic deflector of a toroidal type or a saddle type for deflecting the charged particles in the direction opposite to the direction of deflection of the charged particles caused by the electrostatic deflector.
 67. An E×B separator (6040) for forming an electric field and a magnetic field intersecting at right angles with an optical axis and separating at least two charged particles traveling in different directions, comprising: an electrostatic deflector having at least six electrodes for forming a rotatable electric field; and an electromagnetic deflector of a toroidal type or a saddle type for deflecting the charged particles in the direction opposite to the direction of deflection of the charged particles caused by the electrostatic deflector.
 68. The E×B separator of claim 66 or 67, wherein the electromagnetic deflector of the toroidal type or the saddle type comprises two sets of electromagnetic coils for generating magnetic fields in both directions of electric fields and magnetic fields; and the direction of deflection caused by the electromagnetic deflector is set to become opposite to the direction of deflection caused by the direction of deflection by the electrostatic deflector by adjusting a rate of currents flowing through the two sets of the electromagnetic coils.
 69. The E×B separator of claim 68, wherein the electrostatic deflector is disposed inside the electromagnetic deflector of the saddle type or the toroidal type.
 70. An inspection apparatus (6000) for evaluating a processed state of a semiconductor wafer by irradiating the semiconductor wafer with a plurality of primary charged particle, detecting the plurality of the secondary charged particles from the semiconductor wafer with a plurality of detectors, and obtaining image data, wherein the E×B separator of claim 68 is used for separating the secondary charged particles from the primary charged particles.
 71. An inspection apparatus (7000) wherein a sample is placed on an XY-stage and charged particles are irradiated onto the sample, and wherein the XY-stage is contained in a housing and supported on the housing in a non-contact supporting state by a hydrostatic bearing, the housing which contains the stage is evacuated into a vacuum state, and a differential exhausting mechanism is provided around the portion of the inspection apparatus for irradiating charged particles onto a surface of the sample so as to evacuate an area of the sample where charged particles are irradiated.
 72. The inspection apparatus of claim 71, wherein a gas to be fed to the hydrostatic bearing of the XY-stage is nitrogen or an inert gas, and the nitrogen or the inert gas is pressurized after being exhausted from the housing which contains the stage and is again supplied to the hydrostatic bearing.
 73. An inspection apparatus for inspecting a defect on the surface of a semiconductor wafer by using the inspection apparatus of claim 71 or
 72. 74. An exposure apparatus for delineating a circuit pattern of a semiconductor device on a surface of the semiconductor wafer or a reticle by using the inspection apparatus of claim 71 or
 72. 75. A method for manufacturing semiconductors by using the inspection apparatus of any one of claims 71 to
 74. 76. A setting method for an inspection apparatus (8000), for reducing an aberration of a formed image in the inspection apparatus in which a plurality of charged particles is focused by a lens system including a condenser lens and then formed into an image on a sample by an objective lens, said method comprising the steps of: varying a crossover position of the charged particles produced in the vicinity of the objective lens by the lens system, by adjusting the lens system measuring values of aberration in the formed image varying along with a variation of the crossover position; identifying the crossover position corresponding to a range where the value of aberration is under a predetermined value, based on the measured values; and setting the crossover position at the identified position by adjusting the lens system.
 77. An inspection apparatus (8000) in which a plurality of charged particles is focused by a lens system including a condenser lens and then formed into an image on a sample by an objective lens, wherein a crossover position is set to such position where the values of aberration is under a predetermined value, which is determined by varying a crossover position by adjusting the lens system, and measuring values of aberration in the formed image varying along with a variation of the crossover position.
 78. The inspection apparatus of claim 77, wherein the crossover position is set taking a chromatic aberration of magnification as the aberration.
 79. The inspection apparatus of claim 77, wherein the plurality of charged particles is a plurality of charged particles which is emitted from a single beam generating means and then passes through a plurality of apertures to be formed into the plurality of charged particles, a plurality of charged particles emitted from a plurality of beam generating means, or a plurality of charged particles emitted from a plurality of emitters formed in a single beam generating means.
 80. The inspection apparatus of any one of claims 77 to 79, wherein the crossover position is set to a side of the lens system with respect to a principal plane of the objective lens.
 81. A device manufacturing method for evaluating a wafer during manufacturing process by using the inspection apparatus of any one of claims 77 to
 80. 82. An electron beam apparatus (5000) comprising a primary optical system for generating a primary electron beam, converging it, and irradiating a sample by scanning with the primary electron beam, a secondary optical system for receiving secondary electrons emitted from a portion of the sample where the primary electron beam is irradiated, said secondary optical system having a lens of at least one stage, and a detector for detecting the secondary electrons, wherein the secondary electrons emitted from the portion of the sample where the primary electron beam is irradiated are accelerated and separated from the primary optical system by an E×B separator to be introduced into the secondary optical system, and an image of the secondary electrons is magnified by the lens to be detected by a detector, wherein the primary optical system generates a plurality of the primary electron beams and irradiates the sample therewith concurrently, and a plurality of the detectors is disposed so that a number thereof corresponds to the number of the primary electron beams; and the electron beam apparatus comprises a retarding voltage applying unit for applying an retarding voltage to the sample, and a charging investigating function for investigating a charged-up status of the sample, wherein an optimum retarding voltage is determined based on an information about the charging status from the charging investigating function, and then the optimum retarding voltage is applied to the sample or an irradiation amount of the primary electron beam is varied.
 83. An inspection apparatus (4300) comprising a primary optical system having a single beam generating means for discharging a beam, an aperture plate with a plurality of apertures, a plurality of lenses, and an E×B separator so as to irradiate a surface of a sample to be inspected with the beam emitted from the beam generating means, and a secondary optical system for separating secondary charged particles emitted from the sample from the primary optical system by the E×B separator so as to introduce them into a secondary charged particle detector to be detected therein; wherein the beam from the beam generating means is irradiated onto the aperture plate to form an image of the plurality of apertures, a position of the image of the plurality of apertures is made to correspond to a position of the E×B separator, and a scanning voltage is superimposed on an electric field of the E×B separator so as to cause a deflecting operation of the beam.
 84. An inspection method for inspecting an object to be inspected by irradiating the object to be inspected with either one of charged particles or an electromagnetic wave, wherein a working chamber controllable into a vacuum atmosphere for inspecting an object to be inspected, a beam generating means for generating either one of charged particles or an electromagnetic wave as a beam, an electronic optical system in which a plurality of the beams is irradiated onto the object held in the working chamber so as to be inspected and secondary charged particles generated from the object to be inspected are detected so as to introduce them into an image processing system, an image processing system for forming an image by the secondary charged particles, a data processing system for displaying and/or storing a state information of the object to be inspected based on an output from the image processing system, and a stage system for operatively holding the object to be inspected so as to be movable with respect to the beam are provide, said inspection method comprising the steps of: precisely positioning the beam on the object to be inspected by measuring a position of the object to be inspected; deflecting the beam of either of charged particles or electromagnetic wave to a desired position on a surface of the measured object to be inspected; irradiating the desired position on the surface of the object to be inspected with the beam; detecting secondary charged particles generated from the object to be inspected; forming an image by the secondary charged particles; and displaying and/or storing a state information of the object to be inspected based on an output of the image processing system.
 85. An inspection method (1000) for irradiating charged particles to a sample and for detecting secondary charged particles emitted from the sample, wherein at least one primary optical system for irradiating the sample with a plurality of charged particle beams and at least one secondary optical system for leading the secondary charged particles to at least one detector are provided, and the plurality of the charged particle beams are irradiated with each spaced at a position greater than a distance resolution of the secondary optical system.
 86. An inspection method (3000) for inspecting a sample for defects, comprising the steps of: acquiring an image of a plurality of inspection regions that are displaced from each other while partially overlapping with each other on the surface of the sample; storing a reference image; and deciding a defect of the sample by comparing an image of each of the plurality of the inspection regions acquired in the step of acquiring with the reference image stored in the step of storing.
 87. The inspection method of claim 86, wherein an electronic optical system (3100) comprising a source of particles for discharging primary charged particles and a deflecting means for deflecting the primary charged particles is provided, and the plurality of the inspection regions are irradiated one after another with the primary charged particles by deflecting the primary charged particle with the deflecting means.
 88. An inspection method (4100) comprising the steps of: irradiating a beam emitted from a single beam generating means to an aperture plate with a plurality of apertures; irradiating charged particles passed through the plurality of apertures to a sample by a primary optical system; separating secondary charged particles generated from the sample from the primary optical system by an E×B separator; and delivering the separated secondary charged particles through a secondary optical system having at least one stage lens into a plurality of detectors so as to be detected.
 89. An inspection method (4100) comprising the steps of: irradiating a beam emitted from a beam generating means with an integrated cathode to an aperture plate with a plurality of apertures; focusing and irradiating beams passed through the plurality of apertures onto a sample surface by a primary optical system; separating secondary charged particles generated from the sample from the primary optical system by an E×B separator; and delivering the separated secondary charged particles through a secondary optical system having at least one stage lens and into a plurality of detectors so as to be detected.
 90. An inspection method (4100) comprising the steps of: delivering a plurality of images of apertures to a sample, said plurality of images of apertures being produced by irradiating a beam emitted from a beam generating means onto an aperture plate having a plurality of apertures; and separating secondary charged particles generated from the sample from a primary optical system to be delivered into a secondary optical system, and enlarging the secondary charged particles by the secondary optical system to be projected onto a surface of a detector; said method further comprising: disposing a single aperture plate in a position deviated toward the side of the beam generating means from a position of an image of the beam generating means formed by a lens of the primary optical system; and disposing the position of the single aperture plate in the direction of an optical axis thereof so as to minimize a difference in beam strength of the beams to be delivered from each aperture to the surface of the sample.
 91. An inspection method (4100) comprising the steps of: delivering a plurality of images of apertures onto a sample, said plurality of images of apertures being produced by irradiating a beam emitted from a beam generating means to an aperture plate having a plurality of apertures; and separating secondary charged particles generated from the sample from a primary optical system to be delivered into a secondary optical system, and enlarging the secondary charged particles by the secondary optical system to be projected to a surface of a detector; wherein a single aperture plate is disposed in a position deviated toward the side of the beam generating means from a position of an image of the beam generating means formed by a lens of the primary optical system; and an amount of deviation is set such that an amount of detection of the secondary charged particles obtained when a sample with no pattern is disposed on a surface of the sample minimizes a difference thereof between the plurality of the apertures.
 92. An inspection method (4200) comprising the steps of: irradiating a first multi-aperture plate having a plurality of apertures with beams emitted from one or more beam generating means; projecting and scanning a reduced image of primary charged particles passed through the plurality of the apertures onto a sample by using a primary optical system; and enlarging secondary charged particles emitted from the sample, by a secondary optical system to detect them by a detector having a plurality of detecting elements; and disposing a second multi-aperture plate with a plurality of apertures in front of the detector; wherein positions of the apertures formed in the second multi-aperture plate are arranged so as to correct a distortion of the secondary optical system.
 93. An inspection method (4300) comprising the steps of: providing a primary optical system comprising a single beam generating means for discharging a beam, an aperture plate with a plurality of apertures, a plurality of lenses, and an E×B separator, so as to irradiate a surface of a sample to be inspected with the beam emitted from the beam generating means; and separating secondary charged particles emitted from the sample from the primary optical system by the E×B separator so as to introduce them into a secondary charged particle detector to be detected therein; wherein the beam from the beam generating means is irradiated onto the aperture plate to form an image of the plurality of apertures, and a scanning voltage is superimposed on an electric field of the E×B separator so as to cause a deflecting operation of the beam.
 94. An inspection method (4400) comprising the steps of: irradiating a sample with a plurality of primary charged article beams by a primary optical system; and delivering secondary charged particles emitted from the sample, after having passed through an objective lens, into a secondary optical system by an E×B separator, thereafter increasing a distance between secondary charged particle beams by at least one stage of lens, and detecting the secondary charged particle beams by a plurality of detectors; wherein at least three different energizing voltages are separately supplied to the objective lens so as to take at least three data measurements which represent rising widths of electric signals corresponding to strength of the secondary charged particles and which are obtained when a pattern edge parallel with a first direction is scanned in a second direction.
 95. An inspection method (4400) comprising the steps of: irradiating a sample with a plurality of primary charged particles by a primary optical system; and delivering secondary charged particles emitted from the sample, after having passed through an objective lens, into a secondary optical system by an E×B separator, thereafter enlarging a distance between secondary charged particle beams by at least one stage of lens, and detecting the secondary charged particle beams by a plurality of detectors; wherein the objective lens comprises a first electrode to which a first voltage near earth is applied and a second electrode to which a second voltage higher than the first voltage is applied, and a focal length of the objective lens is varied by changing the first voltage applied to the first electrode; and an energizing means for energizing the objective lens comprises a means for changing the voltage applied to the second electrode for significantly changing the focal length of the objective lens, and a means for changing the voltage applied to the first electrode for changing the focal length in a short time.
 96. An inspection method (4500) comprising the steps of: converting a beam emitted from a single beam generating means into multi-beams by an aperture plate having a plurality of apertures; reducing the multi-beams by an electrostatic lens of at least two stages by a primary optical system, and scanning a sample to be inspected; and separating the secondary charged particle beams emitted from the sample, after having passed through an electrostatic objective lens, from the first optical system by an E×B separator, thereafter enlarging the secondary charged particle beams by an electrostatic lens of at least one stage, and delivering the secondary charged particle beams to a plurality of detection devices; wherein the sample is evaluated by at least two kinds of pixel dimensions so as to enable the sample to be evaluated in a mode in which throughput is high yet a resolution is relatively low and also in another mode in which throughput is small yet resolution is high.
 97. An inspection method (5000) comprising the steps of: providing a primary optical system for generating primary charged particles, converging them, and irradiating a sample by scanning with the primary charged particles, and a secondary optical system for receiving secondary charged particles emitted from portions of the sample where the primary charged particles are irradiated, said secondary optical system having a lens of at least one stage; and accelerating the secondary charged particles emitted from the portions of the sample where the primary charged particles are irradiated, separating the secondary charged particles from the primary optical system by an E×B separator so as to enter the secondary optical system, and magnifying an image of the secondary charged particles by the lens to be detected by a detector; said method further comprising the steps of: generating a plurality of the primary charged particles by the primary optical system and irradiating the sample concurrently therewith; providing a plurality of the detectors so that the number thereof corresponds to that of the primary charged particles beams; applying a retarding voltage to the sample; and investigating a charged-up status of the sample.
 98. An inspection method using an apparatus (5000) comprising an optical system for irradiating a sample with a plurality of charged particles and a charging investigating function, wherein the charging investigating function evaluates a distortion of a pattern or a fading of a pattern at a specific portion of the sample when secondary charged particles generated by irradiating the sample with primary charged particles are detected by a plurality of detectors to form an image, and evaluates a charging to be large when the distortion of the pattern or the fading thereof is determined as large.
 99. An inspection method (7000) for irradiating a sample placed on an XY-stage with charged particles, wherein the XY-stage is contained in a housing and supported on the housing in a non-contact supporting state by a hydrostatic bearing, the housing which contains the stage is evacuated into a vacuum state, and a differential exhausting mechanism is provided around a portion of the inspection apparatus for irradiating the charged particles to a surface of the sample so as to evacuate an area of the sample where charged particles are to be irradiated.
 100. An inspection method (4300) comprising the steps of: providing a primary optical system comprising a single beam generating means for discharging a beam, an aperture plate provided with a plurality of apertures, a plurality of lenses and an E×B separator so that the beam from the beam generating means is irradiated onto a surface of a sample; and separating secondary charged particles emitted from the sample from the primary optical system by the E×B separator so as to enter a secondary charged particle detecting device to be detected thereby; wherein the beam from the beam generating means is irradiated onto the aperture plate to form an image of the plurality of apertures, a position of the image of the plurality of apertures is made to correspond to a position of the E×B separator, and a scanning voltage is superimposed on an electric field of the E×B separator so as to deflect the beam. 